The peninsula occupies the north-western corner of Grande Terre and is named after Jean Loranchet, the first officer of Raymond Rallier du Baty’s second Kerguelen survey expedition in 1913. It has a rugged, mountainous interior, with altitudes exceeding 500 m and a coastline of steep cliffs deeply incised by fjords. It is some 50 km long with a width of up to 20 km. As with most of Grande Terre, it is infested with introduced feral cats, rats and rabbits. Human visitation is infrequent.^[1]

The northern end of the peninsula, and the northernmost part of Grande Terre, extending northwards from the head of the Baie de la Dauphine, has been identified as a 60 km² Important Bird Area (IBA) by BirdLife International because of its breeding seabirds. At least 23 bird species breed in the IBA. As well as a colony of 250,000 pairs of macaroni penguins at the tip of the peninsula, there are also 5,400 pairs of southern rockhopper penguins and a small colony of 400 pairs of black-browed albatrosses. Cape petrels and Kerguelen shags nest on the cliffs. Other birds include light-mantled albatrosses, Kerguelen terns and Eaton's pintails. Antarctic fur seals and southern elephant seals breed in the IBA.^[1]

48°42′S 69°00′E / 48.700°S 69.000°E / -48.700; 69.000