The Kodiak National Wildlife Refuge includes the southwestern two-thirds of Kodiak Island, Uganik Island, the Red Peaks area of Afognak Island and all of Ban Island in the archipelago. It encompasses about 7,700 km² (3,000 sq miles).
The climate of the refuge is that of southern Alaska, mild and rainy. Many areas in the refuge are densely forested with Sitka Spruce at lower elevations. There are grasslands in drier areas and at higher elevations. The refuge contains several small glaciers.
The refuge has no road access from outside and contains no roads.