It is mostly in the arrondissement of Fontainebleau in the southwestern part of the department of Seine-et-Marne. Parts of it are in adjoining cantons, and even as far west as the town of Milly-la-Forêt in the neighboring department, Essonne. Several "communes" are in the forest, notably the towns of Fontainebleau and Avon. The forest has an area of .