Peterson Island (66°28′S110°30′E) is an Antarctic rocky island, 2 mi long, with two inlets indenting the north side, lying immediately west of Browning Peninsula in the south part of the Windmill Islands. It was first mapped from air photos taken by USN Operation Highjump and Operation Windmill in 1947 and 1948. It was named by the US-ACAN for Lt. Mendel L.