The River l’École forms the eastern boundary of Oncy-sur-École; Mesolithic rock engravings can be found on the rocky slopes of the Mont Grippon massif. Other highlights include the 11th-century Romanesque church of Saint-Martin, a biographical connection dating back to the 18th century, and Menthe poivrée de Milly peppermint. These subjects span everything from early human history to architectural and product culture. When planning your visit, you can focus on the landscape, sacred art or regional production.
Landscape and Early Traces
The river forms the eastern boundary of the village, while the engravings are found on the rocky slopes of Mont Grippon. These are distinct landscape features: the watercourse marks the edge of the village, while the rock points to traces of early human activity. The Mesolithic is the Middle Stone Age, so the engravings date to a much earlier period than the church’s construction. If you are interested in archaeology, you can explore this early history as a separate focus alongside the religious and architectural heritage.
You can easily distinguish between these themes: Mont Grippon represents prehistoric traces in the landscape, while Saint-Martin represents Romanesque architecture and protected religious art. This brings together landscape history and architectural history without requiring you to view them from the same perspective.
Saint-Martin and Local History
Saint-Martin church was built in the 11th century and is one of the oldest churches in the Essonne department. It has been awarded the “Patrimoine d’Intérêt Régional” label, a regional heritage designation. Inside are a 13th-century Madonna and Child and a statue of Saint Anne; both works of art are classified as historic monuments. The chronology is clear: the Madonna and Child dates from a later period than the church building. The regional designation applies to the church, while the classification as historic monuments applies to the two works of art. Saint-Martin can therefore be understood in terms of its age, regional recognition and individual works of art.
Simon Mathurin Lantara was born in Oncy-sur-École on 24 March 1729. This biographical connection adds a person from the village’s history to the archaeological and church-history themes.
Regional Products and Activities
Ferme du Clos d’Artois is now the last producer of Menthe poivrée de Milly. This peppermint adds regional product culture to the historical themes and offers a different focus from the church and archaeological landscape. If you are also interested in regional produce during your trip, it offers another point of interest.
A 2020 tour guide describes a geocaching route in Oncy-sur-École with five hidden caches. Check the current status of the route and caches before your trip. The 2025 edition of the traditional “La Milliacoise” mountain biking and gravel cycling event offered seven routes in the Fontainebleau forest massif and the forest of Oncy-sur-École.
The activities differ in character: geocaching centres on searching for hidden caches, while the 2025 edition of the cycling event offered a choice of seven routes across two forest areas.
Discover more destinations: Montlhéry, Villeneuve-Sur-Auvers, Paray-Vieille-Poste, Chilly-Mazarin, Saintry-sur-Seine, Yerres, Lisses, Ormoy.
For the broader travel overview: Essonne.
