4.6
(1773)
14,520
hikers
383
hikes
Hiking around Oncy-Sur-École offers diverse landscapes within the Parc Naturel Régional du Gâtinais Français, often called the "land of a thousand glades and sandstone." The area features a mix of forests, agricultural fields, valleys, and the École River, providing varied terrain for exploration. Mount Grippon borders the village, contributing to the hilly landscape, and the region benefits from its proximity to the Fontainebleau forest, known for its unique sandstone formations and woodlands.
Last updated: May 11, 2026
4.5
(18)
59
hikers
12.0km
03:09
90m
90m
Moderate hike. Good fitness required. Easily-accessible paths. Suitable for all skill levels.
4.9
(7)
33
hikers
Moderate hike. Good fitness required. Easily-accessible paths. Suitable for all skill levels.

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4.3
(3)
13
hikers
Moderate hike. Good fitness required. Easily-accessible paths. Suitable for all skill levels.
4.7
(3)
13
hikers
Moderate hike. Good fitness required. Easily-accessible paths. Suitable for all skill levels.
6
hikers
Easy hike. Great for any fitness level. Easily-accessible paths. Suitable for all skill levels.
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The mill is said to be over two thousand years old. Joan of Arc stayed there and Louis XI is said to have donated it to his advisor Olivier le Daim.
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Former market square in the heart of Milly-la-Forêt.
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The cyclops visit is not free, 12 euros entry but it lasts 45 minutes and is very interesting. Limit of 25 people at a time. Please note that photos inside are prohibited. I recommend the first visit at 10:30 a.m. (less crowded)
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The trail moves on to the main essentials The hall In 1479, by a special grace from Louis The North-South facing Hall, 46 m long, 16 m wide and 13 m high, covers a total surface area of 730 m2. 48 oak pillars, resting on “dice”-cut stone bases, support a chestnut frame typical of Ile-de-France at that time; this frame presents to the north (on the rue Langlois side) a “pavilion” farm. Today, La Halle is still the site of a market on Thursday afternoons. The square, the houses gathered all around, bear witness to the great commercial activity which already reigned in the region 500 years ago. La Halle has been classified as a Historic Monument since 1923. Bonde Castle is located near the town center of Milly-la-Forêt, Built near an artificial island in the l'École river to the west of the Notre-Dame collegiate church, its park is bordered to the west by the course of the river which forms a moat to the north protecting the châtelet. History Built in the 12th century by the lords of Milly, the castle was ruined during the English siege in 1432. At the end of the 15th century around 1475, owned by Admiral Louis Malet de Graville, it was rebuilt and enlarged. What was then the keep became the entrance gatehouse, the drawbridge was replaced by a permanent stone bridge and a gate closed access between the northern defense tower and the governor's house. A square courtyard was surrounded by a wall and had in the center a chapel dedicated to Saint Valentine. The castle was successively the property of Hugues III de Bouville, Olivier V de Clisson, Jean II de Montmorency, Jean-François de Faudoas d'Averton, Marc-Antoine Front de Beaupoil de Saint-Aulaire and Pierre Marie of Lau d’Allemans. In the 19th century, the towers of the chatelet were enhanced with brick battlements and a slender roof. In 1859 the Corne bridge was rebuilt near the castle washhouse which served as a watering trough for the animals. At the end of the 20th century the mills along the river were demolished. In 1964, the Bonde washhouse downstream of the river which was part of the estate was rehabilitated. On December 20, 1972, the castle was partly listed as a historic monument. The park was listed in 1991 for its fences, canals and paths. the house of Jean Cocteau. Entrance to the J. Cocteau house [This 17th century residence, flanked by turrets, was formerly called the Governor's House. It corresponds to an old outbuilding of the castle in front of which the vassals came to pay homage and faith to their lord. Jean Cocteau bought this house with Jean Marais in 1947 and lived there until his death. Notre-Dame de l’Assomption Church Founded in the 11th century, the former chapel of the castle, it was rebuilt around 1485 on the orders of Admiral de Graville in the Gothic style of the 13th and 14th centuries. The bell tower, 57 meters high, dates from the 11th century in its lower part and from the 12th and 13th centuries in its upper part. The arch of the main portal in the primitive Romanesque style comes from an old church in Milly (Saint-Pierre or Saint-Jacques). On the east side of the bell tower - Place Grammont side - the arms of Admiral de Graville are still visible. Many works of sacred art are found inside the church. The church was listed as a Historic Monument in 1926. The dovecote; Located on the old triangular square of the dovecote cul de sac, this old building was part of the Domaine du Moustier, property of Fulbert I, lord of Milly and officer at the court of Dagobert I in the 7th century. Destroyed in 1432 or 1433, the complex included a vast farm. According to a count in 1792 it had around 1200 niches. Only the lords held the right to build these premises designed for breeding. The Moustier de Péronne gate is one of the oldest vestiges of Milly and dates from the 7th century. It provided access to the moustier (monastery in old French) owned by Fulbert I, who obtained the land of Milly from Dagobert I. His son Wulfran was born there around the year 635. Entering religion, he became the apostle of the frieze (Netherlands), then bishop of Sens before retiring to Saint Wandrille where he died in 720.
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Miily-la-Forêt is a charming country town, in the heart of Gatinais. Ideal as a base from which to visit the forest of Fontainebleau and its famous rocks!
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This sculpture, made of concrete and iron, represents the fantastic creature from Greek mythology which gave its name to the work. 22.5 meters high, the sculpture is a project by artists Jean Tinguely and Niki de Saint Phalle, carried out between 1969 and 1994. On site, you can also discover two other works: the Face of Mirrors and the Tribute to the Deportees. Visiting all the monuments is completely free.
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There are nearly 400 hiking routes around Oncy-Sur-École, offering a wide range of options for all skill levels. You'll find everything from easy strolls to more challenging excursions through varied landscapes.
Yes, Oncy-Sur-École offers over 150 easy hiking trails perfect for beginners or families. These routes often traverse the gentle terrain of the Parc Naturel Régional du Gâtinais Français, providing pleasant walks through forests and fields. An example of an easy route is the Milly-la-Forêt – Milly-la-Forêt Village Center loop from Milly-la-Forêt, which is about 4.7 km long.
Hiking around Oncy-Sur-École offers a diverse tapestry of landscapes. You'll encounter the contrasting features of the Parc Naturel Régional du Gâtinais Français, including forests, agricultural fields, valleys, and the École River. The area also borders Mount Grippon, suggesting hilly terrain, and benefits from its proximity to the Fontainebleau forest, known for its unique sandstone formations and diverse woodlands.
Yes, many of the hiking trails around Oncy-Sur-École are circular, allowing you to start and end at the same point. For instance, the Market Hall of Milly-la-Forêt – Milly-la-Forêt Village Center loop from Milly-la-Forêt is a moderate 9 km circular route that takes you through the village and surrounding countryside.
The region around Oncy-Sur-École integrates cultural and historical points of interest into its trails. You might encounter unique art installations like The Cyclop by Jean Tinguely and Niki de Saint Phalle, which is featured on the Milly-la-Forêt Village Center – The Cyclop loop from Milly-la-Forêt. Other notable attractions include the historic Domaine de Courances and various natural monuments like Béorlots Sand Dune and Les sables du Cul de Chien.
The hiking experience in Oncy-Sur-École is highly rated by the komoot community, with an average score of 4.7 stars from over 1,600 reviews. Hikers often praise the diverse woodlands, the unique sandstone formations, and the peaceful river valleys that characterize the region. The variety of routes, from easy strolls to more challenging excursions, also contributes to its popularity.
While Oncy-Sur-École is located within the Parc Naturel Régional du Gâtinais Français, its close proximity to the vast Fontainebleau Forest means many trails in the broader region offer access to its unique geological formations, sandy paths, and diverse woodlands. Routes like the Milly-la-Forêt and Coquibus Trail explore varied woodlands and open areas that are characteristic of this wider forest region.
Yes, the area offers trails that incorporate historical sites. For example, the Milly-la-Forêt Village Center – Domaine de Courances loop from Milly-la-Forêt will lead you past the impressive Domaine de Courances, a notable castle and its grounds.
The diverse landscapes of Oncy-Sur-École, with its forests and fields, are enjoyable throughout much of the year. Spring and autumn offer pleasant temperatures and beautiful scenery, with vibrant foliage in fall. Summer is also popular, though some trails may be more exposed. Winter hikes can be serene, especially in the woodlands, but require appropriate gear.
Yes, for those seeking a greater challenge, there are over 90 difficult trails in the region. These routes often involve longer distances and more varied terrain, sometimes including the rocky formations found in areas bordering the Fontainebleau forest. These are suitable for experienced hikers with good fitness.
Absolutely. Oncy-Sur-École is nestled in the heart of the Parc Naturel Régional du Gâtinais Français, making it an excellent base for exploring this 'land of a thousand glades and sandstone.' The village itself is bordered by Mount Grippon and traversed by the École River, providing immediate access to the park's characteristic mix of forests, agricultural fields, and valleys. For more information on the park, you can visit visitparisregion.com.
The region's proximity to the Fontainebleau forest means that many trails will lead you through areas characterized by unique sandstone formations and boulders. While specific routes are not named for these features, exploring the woodlands and plateaus around Oncy-Sur-École will often bring you into contact with this distinctive geology, especially in areas like the Coquibus.


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