The Courbet Peninsula (Péninsule Courbet) is a vast peninsula occupying the northeastern portion of the principal island of Kerguelen. In the south of the peninsula is Port-aux-Français, the principal station of the archipelago.
The peninsula is relatively flat, with altitudes not exceeding 200m.
The southern frontage of the Courbet Peninsula faces the presqu'île Ronarc'h and thus is the northern part of the Gulf of Morbihan. The main land is to the east, connected via a pass called Passe Royale and which skirts the short peninsula which prolongs the peninsula at the south-east, the presqu'île du Prince de Galles. To the north of this peninsula is a small bay called Norwegian Bay.
At the east is a coastal lake called Lake Marly, north of the easternmost point of Kerguelen called Cape Ratmanoff. Continuously towards the north, one reaches then Cape Digby, which roughly marks the north-western point of the peninsula. The northernmost point of the peninsula is Cape Cotter.
In addition to Port-aux-Francais is a former observatory site called Molloy, 10 km west along the south coast of the Courbet Peninsula, or northern shore of the Golfe du Morbihan. An American expedition led by G. P. Ryan erected a station at this site on 7 September 1874. This station was also established to track the 1874 Transit of Venus.