Debuting on September 13–14, 2025, the Festival des 3 Forêts offers one of the first ultra-trail experiences in Île‑de‑France, starting in Mériel and linking three iconic forest massifs: Carnelle, Île‑Adam, and Montmorency. . Runners can choose from seven distances—ultra-trail options of 162 km (4 800 m+), 100 km (2 500 m+), 70 km (1 700 m+), 65 km (2 500 m+), 45 km (1 500 m+), 25 km (650 m+), and a 13 km loop (300 m+)—with events spanning both days. . The scenic routes traverse woodland trails, Vexin naturel park, riverside paths, and quaint villages, with multiple aid stations, water points, and generous cutoff times (up to 36 h for the 162 km ultra). . Organisers aim to blend ultrarunning performance with regional discovery, showcasing local heritage and inviting community support for this inaugural event.
Races
162 km
100 km
70 km
65 km
45 km
25 km
13 km
13 km
Race Date:
13 September, 2025
The flagship race of the weekend, this 162 km ultra begins on Saturday, September 13, 2025, and spans two days with a total elevation gain of about 5,000 meters. Coordinated by Sport Nature pour Tous, it is the first 100-mile trail event in Île-de-France, offering an epic tour of the Carnelle, Montmorency, and l’Isle-Adam forests.
Race Date:
13 September, 2025
Starting on Saturday, September 13, 2025, the 100 km ultra-trail offers approximately 2,500 meters of elevation gain over forested and rural trails. Organized by Sport Nature pour Tous, it stands out as one of the region’s premier ultra-distance experiences.
Race Date:
13 September, 2025
The 70 km trail race runs on September 13–14, 2025, with a total ascent of around 1,700 meters through the forests of the Val-d’Oise. Hosted by Sport Nature pour Tous, this course blends runnable paths with varied terrain for an ideal ultra-trail training race.
Race Date:
14 September, 2025
Taking place over September 14, 2025, the 65 km event features approximately 2,500 meters of elevation gain, covering extended forest terrain and technical sections. Managed by Sport Nature pour Tous, this long-format trail is ideal for seasoned athletes aiming for a serious endurance test.
Race Date:
14 September, 2025
Held on Sunday, September 14, 2025, this 45 km course delivers roughly 1,500 meters of elevation gain through the interconnected trails of three major forests. Organized by Sport Nature pour Tous, it’s designed for experienced runners looking for a demanding yet scenic adventure.
Race Date:
14 September, 2025
The 25 km race takes place on Sunday, September 14, 2025, with a route that includes about 650 meters of elevation gain across the Carnelle and Montmorency forests. Hosted by Sport Nature pour Tous, this intermediate challenge highlights the natural beauty of the Île-de-France woodlands.
Race Date:
14 September, 2025
Scheduled for Sunday, September 14, 2025, the 13 km trail begins in Mériel and takes runners on a scenic loop through forested trails, with approximately 300 meters of elevation gain. Organized by Sport Nature pour Tous, this short-distance race offers an accessible introduction to trail running in the lush landscapes of Val-d’Oise.
Race Date:
14 September, 2025
Scheduled for Sunday, September 14, 2025, the 13 km trail begins in Mériel and takes runners on a scenic loop through forested trails, with approximately 300 meters of elevation gain. Organized by Sport Nature pour Tous, this short-distance race offers an accessible introduction to trail running in the lush landscapes of Val-d’Oise.
Weather based on historical averages.
FAQs
What is the Forets 162?
How long is the Forets 162?
Where does the Forets 162 take place?
What is the elevation gain of the Forets 162?
How can I prepare for the Forets 162?
How do I choose the right training plan for the Forets 162?
The flagship race of the weekend, this 162 km ultra begins on Saturday, September 13, 2025, and spans two days with a total elevation gain of about 5,000 meters. Coordinated by Sport Nature pour Tous, it is the first 100-mile trail event in Île-de-France, offering an epic tour of the Carnelle, Montmorency, and l’Isle-Adam forests.
The Forets 162 is 162km long.
The Forets 162 takes place in Mériel, France.
The Forets 162 elevation gain is 5000 metres, which Runna classifies as a Hilly race.
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Forets 162?
The flagship race of the weekend, this 162 km ultra begins on Saturday, September 13, 2025, and spans two days with a total elevation gain of about 5,000 meters. Coordinated by Sport Nature pour Tous, it is the first 100-mile trail event in Île-de-France, offering an epic tour of the Carnelle, Montmorency, and l’Isle-Adam forests.
How long is the Forets 162?
The Forets 162 is 162km long.
Where does the Forets 162 take place?
The Forets 162 takes place in Mériel, France.
What is the elevation gain of the Forets 162?
The Forets 162 elevation gain is 5000 metres, which Runna classifies as a Hilly race.
How can I prepare for the Forets 162?
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
How do I choose the right training plan for the Forets 162?
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Forets 100?
How long is the Forets 100?
Where does the Forets 100 take place?
What is the elevation gain of the Forets 100?
How can I prepare for the Forets 100?
How do I choose the right training plan for the Forets 100?
Starting on Saturday, September 13, 2025, the 100 km ultra-trail offers approximately 2,500 meters of elevation gain over forested and rural trails. Organized by Sport Nature pour Tous, it stands out as one of the region’s premier ultra-distance experiences.
The Forets 100 is 97km long.
The Forets 100 takes place in Mériel, France.
The Forets 100 elevation gain is 2500 metres, which Runna classifies as a Hilly race.
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Forets 100?
Starting on Saturday, September 13, 2025, the 100 km ultra-trail offers approximately 2,500 meters of elevation gain over forested and rural trails. Organized by Sport Nature pour Tous, it stands out as one of the region’s premier ultra-distance experiences.
How long is the Forets 100?
The Forets 100 is 97km long.
Where does the Forets 100 take place?
The Forets 100 takes place in Mériel, France.
What is the elevation gain of the Forets 100?
The Forets 100 elevation gain is 2500 metres, which Runna classifies as a Hilly race.
How can I prepare for the Forets 100?
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
How do I choose the right training plan for the Forets 100?
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Forets 70?
How long is the Forets 70?
Where does the Forets 70 take place?
What is the elevation gain of the Forets 70?
How can I prepare for the Forets 70?
How do I choose the right training plan for the Forets 70?
The 70 km trail race runs on September 13–14, 2025, with a total ascent of around 1,700 meters through the forests of the Val-d’Oise. Hosted by Sport Nature pour Tous, this course blends runnable paths with varied terrain for an ideal ultra-trail training race.
The Forets 70 is 71km long.
The Forets 70 takes place in Mériel, France.
The Forets 70 elevation gain is 1700 metres, which Runna classifies as a Hilly race.
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Forets 70?
The 70 km trail race runs on September 13–14, 2025, with a total ascent of around 1,700 meters through the forests of the Val-d’Oise. Hosted by Sport Nature pour Tous, this course blends runnable paths with varied terrain for an ideal ultra-trail training race.
How long is the Forets 70?
The Forets 70 is 71km long.
Where does the Forets 70 take place?
The Forets 70 takes place in Mériel, France.
What is the elevation gain of the Forets 70?
The Forets 70 elevation gain is 1700 metres, which Runna classifies as a Hilly race.
How can I prepare for the Forets 70?
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
How do I choose the right training plan for the Forets 70?
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Forets 65?
How long is the Forets 65?
Where does the Forets 65 take place?
What is the elevation gain of the Forets 65?
How can I prepare for the Forets 65?
How do I choose the right training plan for the Forets 65?
Taking place over September 14, 2025, the 65 km event features approximately 2,500 meters of elevation gain, covering extended forest terrain and technical sections. Managed by Sport Nature pour Tous, this long-format trail is ideal for seasoned athletes aiming for a serious endurance test.
The Forets 65 is 65km long.
The Forets 65 takes place in Mériel, France.
The Forets 65 elevation gain is 2500 metres, which Runna classifies as a Hilly race.
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Forets 65?
Taking place over September 14, 2025, the 65 km event features approximately 2,500 meters of elevation gain, covering extended forest terrain and technical sections. Managed by Sport Nature pour Tous, this long-format trail is ideal for seasoned athletes aiming for a serious endurance test.
How long is the Forets 65?
The Forets 65 is 65km long.
Where does the Forets 65 take place?
The Forets 65 takes place in Mériel, France.
What is the elevation gain of the Forets 65?
The Forets 65 elevation gain is 2500 metres, which Runna classifies as a Hilly race.
How can I prepare for the Forets 65?
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
How do I choose the right training plan for the Forets 65?
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Forets 45?
How long is the Forets 45?
Where does the Forets 45 take place?
What is the elevation gain of the Forets 45?
How can I prepare for the Forets 45?
How do I choose the right training plan for the Forets 45?
Held on Sunday, September 14, 2025, this 45 km course delivers roughly 1,500 meters of elevation gain through the interconnected trails of three major forests. Organized by Sport Nature pour Tous, it’s designed for experienced runners looking for a demanding yet scenic adventure.
The Forets 45 is 44km long.
The Forets 45 takes place in Mériel, France.
The Forets 45 elevation gain is 1500 metres, which Runna classifies as a Hilly race.
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Forets 45?
Held on Sunday, September 14, 2025, this 45 km course delivers roughly 1,500 meters of elevation gain through the interconnected trails of three major forests. Organized by Sport Nature pour Tous, it’s designed for experienced runners looking for a demanding yet scenic adventure.
How long is the Forets 45?
The Forets 45 is 44km long.
Where does the Forets 45 take place?
The Forets 45 takes place in Mériel, France.
What is the elevation gain of the Forets 45?
The Forets 45 elevation gain is 1500 metres, which Runna classifies as a Hilly race.
How can I prepare for the Forets 45?
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
How do I choose the right training plan for the Forets 45?
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Forets 25?
How long is the Forets 25?
Where does the Forets 25 take place?
What is the elevation gain of the Forets 25?
How can I prepare for the Forets 25?
How do I choose the right training plan for the Forets 25?
The 25 km race takes place on Sunday, September 14, 2025, with a route that includes about 650 meters of elevation gain across the Carnelle and Montmorency forests. Hosted by Sport Nature pour Tous, this intermediate challenge highlights the natural beauty of the Île-de-France woodlands.
The Forets 25 is 25km long.
The Forets 25 takes place in Mériel, France.
The Forets 25 elevation gain is 650 metres, which Runna classifies as a Hilly race.
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Forets 25?
The 25 km race takes place on Sunday, September 14, 2025, with a route that includes about 650 meters of elevation gain across the Carnelle and Montmorency forests. Hosted by Sport Nature pour Tous, this intermediate challenge highlights the natural beauty of the Île-de-France woodlands.
How long is the Forets 25?
The Forets 25 is 25km long.
Where does the Forets 25 take place?
The Forets 25 takes place in Mériel, France.
What is the elevation gain of the Forets 25?
The Forets 25 elevation gain is 650 metres, which Runna classifies as a Hilly race.
How can I prepare for the Forets 25?
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
How do I choose the right training plan for the Forets 25?
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Forets 13?
How long is the Forets 13?
Where does the Forets 13 take place?
What is the elevation gain of the Forets 13?
How can I prepare for the Forets 13?
How do I choose the right training plan for the Forets 13?
Scheduled for Sunday, September 14, 2025, the 13 km trail begins in Mériel and takes runners on a scenic loop through forested trails, with approximately 300 meters of elevation gain. Organized by Sport Nature pour Tous, this short-distance race offers an accessible introduction to trail running in the lush landscapes of Val-d’Oise.
The Forets 13 is 13km long.
The Forets 13 takes place in Mériel, France.
The Forets 13 elevation gain is 300 metres, which Runna classifies as a Hilly race.
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Forets 13?
Scheduled for Sunday, September 14, 2025, the 13 km trail begins in Mériel and takes runners on a scenic loop through forested trails, with approximately 300 meters of elevation gain. Organized by Sport Nature pour Tous, this short-distance race offers an accessible introduction to trail running in the lush landscapes of Val-d’Oise.
How long is the Forets 13?
The Forets 13 is 13km long.
Where does the Forets 13 take place?
The Forets 13 takes place in Mériel, France.
What is the elevation gain of the Forets 13?
The Forets 13 elevation gain is 300 metres, which Runna classifies as a Hilly race.
How can I prepare for the Forets 13?
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
How do I choose the right training plan for the Forets 13?
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Forets 13?
How long is the Forets 13?
Where does the Forets 13 take place?
What is the elevation gain of the Forets 13?
How can I prepare for the Forets 13?
How do I choose the right training plan for the Forets 13?
Scheduled for Sunday, September 14, 2025, the 13 km trail begins in Mériel and takes runners on a scenic loop through forested trails, with approximately 300 meters of elevation gain. Organized by Sport Nature pour Tous, this short-distance race offers an accessible introduction to trail running in the lush landscapes of Val-d’Oise.
The Forets 13 is 13km long.
The Forets 13 takes place in Mériel, France.
The Forets 13 elevation gain is 300 metres, which Runna classifies as a Hilly race.
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
What is the Forets 13?
Scheduled for Sunday, September 14, 2025, the 13 km trail begins in Mériel and takes runners on a scenic loop through forested trails, with approximately 300 meters of elevation gain. Organized by Sport Nature pour Tous, this short-distance race offers an accessible introduction to trail running in the lush landscapes of Val-d’Oise.
How long is the Forets 13?
The Forets 13 is 13km long.
Where does the Forets 13 take place?
The Forets 13 takes place in Mériel, France.
What is the elevation gain of the Forets 13?
The Forets 13 elevation gain is 300 metres, which Runna classifies as a Hilly race.
How can I prepare for the Forets 13?
The best way to train for the next race is to use a personalised training plan that takes into account your current running ability, schedule, and preferences.
This will help you steadily improve your running performance and get ready for the race without risking an injury.
Check out our training plans to find the best running program for your goals!
How do I choose the right training plan for the Forets 13?
Which plan you choose will depend on your experience, schedule, objectives, and the date of the race.
Runna offers personalised training plans for every runner and every goal: Whether this is your first, 10th or 100th race, we'll help you get the most out of your training and smash your goals.
Check out our training plans to find the best running program for your goals!
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This event listing is for informational purposes only. Runna is not affiliated with, endorsed by, or sponsored by Festival des 3 Forêts 2025 or Sport Nature pour Tous. All event details are based on publicly available information and are provided solely to help users discover running events. Runna does not use any official logos, images, or proprietary content from this event or its organiser. Any trademarks or names mentioned are used descriptively to identify the event in a factual manner. For the most accurate and up to date information (including to register or purchase an entry to the event), please visit the Festival des 3 Forêts 2025 website.
