Northernmost of five units of the Alaska Maritime National Wildlife Refuge, the Chukchi Sea Unit contains about 200,000 acres on and off of 500 miles of Alaska's northwestern coast. A small subunit of the Chukchi Sea Unit, Chamisso Island and nearby Puffin Island, were combined as a wildlife refuge in 1912, designated Wilderness in 1975, and added to the AMNWR in 1980.

Chamisso has one large sand spit and a low beach zone surrounding a covering of tundra with a few marshy bogs. Although Chamisso Island is much larger, Puffin Island houses many more nesting birds, especially horned puffins, black-legged kittiwakes, and thick-billed murres who build their nests on the steep-walled cliffs that fall into Spafarief Bay. An unusual sight is horned puffins digging burrows in which to lay their eggs, much like tufted puffins do. Eskimos still cross from the mainland to gather eggs, primarily from kittiwakes and murres.

Nothing lives on the islands except for birds and the occasional fox that wanders over on the frozen sea in winter. Walruses, seals, and whales often may be seen in Spafarief Bay. Boating is dangerous due to frequent storms that blow in during cool summers and frigid winters. Daylight never leaves in mid-June and appears briefly as twilight in mid-December.