Mont-Dauphin is both a municipality and a stronghold in the Hautes-Alpes department. It has the rare particularity of having only one neighboring locality, Eygliers, within which it forms an enclave. The former garrison town extends northeast of Embrun on a fluvioglacial terrace at the confluence of the Durance, Guil, and Chagne valleys. This terrace crossed by the Guil is divided into two plateaus (Mont-Dauphin on the right bank and Simoust on the left one) with a mainly agricultural vocation.