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The Bonnevaux Forest covers the eastern extremity of the Bonnevaux Plateau, and stands about 150m above the Liers Plain. The rocky-clay surface formations give rise to impervious relatively unfertile soil; the beech, chestnut and oak undergrowth is punctuated by numerous small (private) ponds.

This landscape is self-contained, with a limited road network, and is bisected by the D 518, which is part of the Vienne-Grenoble route and one of the variants of the Lyon-Grenoble roadway.

Bonnevaux Forest extends uninterrupted over five to six thousand hectares (12,000-14,000 acres) around Lieudieu, the only clearing, which is barely 300 hectares (720 acres). Its composition and atmosphere closely resemble those of Chambarans , from which it is separated by the plains of Liers and Bièvre, as if the latter had divided a single primeval forest. But it is characterised by a large number of ponds, most of which are private and closed off, rendering accessibility problematic. Like Chambarans, it has been taken over by conifers, which has motivated a search for other types of plantations that would lead to more diversified and suitable forms of woodland growth.