Kodiak Island is a large island on the south coast of Alaska, separated from the Alaska mainland by the Shelikof Strait. It is the largest island in Alaska, with 13,890 sq. km (5,363 sq. miles) of area. It is 160 km (100 miles) long and varies from 16 - 96 km (10 - 60 miles) wide. Kodiak Island is the largest island in the Kodiak Archipelago.

Kodiak Island is mountainous and heavily forested in the north and east and fairly treeless on the south. The island has many ice-free, deep bays that provide sheltered anchorages for boats.

Most of the island is a national wildlife refuge. The Kodiak variety of bear and the Kodiak king crab are native to the island. In 1912 the eruption of Mount Katmai on the mainland blanketed the island with volcanic ash, causing widespread destruction and loss of life.

Kodiak Island was explored in 1763 by Russian fur trader Stepan Glotov. The island was the location of the first permanent Russian settlement in Alaska, founded by Grigory Shelikhov, a fur trader, on Three Saints Bay in 1784. The settlement was moved to the site of present-day Kodiak, Alaska village in 1792 and became the center of Russian fur trading.

Kodiak Island contains the Kodiak Island Burough of Alaska. The largest town on the island is Kodiak.

Salmon fishing is a major occupation; the Karluk River is famous for its salmon run. Livestock farms, numerous canneries, and some copper mining are also prevalent.