The De Mas Rocks, also known as Demas Rocks (63°35′S058°03′W) is a group of rocks off the northwest coast of Trinity Peninsula, Antarctica in the approach to Huon Bay, 3 miles (4.8 km) northeast of Cape Ducorps. Discovered in March 1838 by Captain Jules Dumont d'Urville, who named the rocks after his Lieutenant François Edmond Eugene de Barlatier de Mas of the expedition ship Astrolabe.