The Chantilly forest spreads over 6,300 hectares south of the château and is one of the largest forests in the Île-de-France. It was preserved across centuries as a royal hunting reserve and never fragmented by intensive agriculture; the result is a near-continuous canopy of oak and beech, criss-crossed by long avenues that the Princes of Condé carved through it for hunting and forestry rides.
The avenues — the Allée des Champs Aubin, the Allée des Tonnelles, the Allée Saint-Hubert — converge at carrefours marked by columns or crosses, and at the Carrefour des Lions, where eight rides meet. The straight lines and clear sight lines make it easy to navigate even without a map, though a forest map is sold at the tourist office.
The forest is open to walkers, runners and cyclists at all hours. Horse riders exercise their thoroughbreds along marked tracks early in the morning. Wild boar and roe deer are common; mushroom picking is allowed in season with a personal-use limit.