The Kenai Peninsula in Alaska

The Kenai Peninsula is a large peninsula jutting from the southern coast of Alaska in the United States. It extends approximately 150 miles (240 km) southwest from the Chugach Mountains, south of Anchorage. It is separated from the mainland on the west by the Cook Inlet and on the east by Prince William Sound. Administratively the peninsula is part of the Kenai Peninsula Borough.

The glacier-covered Kenai Mountains (7,000 ft/2,130 m) run along the southeast spine of the peninsula along the coast of the Gulf of Alaska. Much of the range is within Kenai Fjords National Park. The northwest coast along the Cook Inlet is flatter and marshy, dotted with numerous small lakes. Several larger lakes extend through the interior of the peninsula, including Skilak Lake and Tustumena Lake. Rivers include the Kenai River, famous for its salmon population, as well as the Russian River, the Kasilof River, and Anchor River . Kachemak Bay, a small inlet off the larger Cook Inlet, extends into the peninsula's southwest end.

The peninsula includes several of the larger towns in southern Alaska, including Seward on the Gulf of Alaska Coast, Kenai along the Cook Inlet, and Homer, along Kachemak Bay in the south. Homer famously marks a terminus of the paved highway system of North America and is a popular destination for automobile travelers who have driven to Alaska from the lower 48 states. Seward is the southern terminus of the Alaska Railroad.

The peninsula has a coastal climate that is mild, with abundant rainfall. It is one of the few areas in Alaska that allows for agriculture, with a growing season adequate for many crops. The peninsula also has natural gas, petroleum, coal deposits, and abundant commercial and personal use fisheries. Tourism is a major industry.

The name Kenai is probably derived from Kenayskaya, the Russian name for the Cook Inlet.