The peninsula extends approximately 150 miles (240 km) southwest from the Chugach Mountains, south of Anchorage. It is separated from the mainland on the west by Cook Inlet and on the east by Prince William Sound. Most of the peninsula is part of the Kenai Peninsula Borough. Athabaskan and Alutiiq Native groups lived on the peninsula for thousands of years prior to Gerasim Izmailov becoming the first European to explore and map the area in 1789.Read more