With an area of 843 square miles (2,183 km2), it is the 15th largest island in the United States.

These three communities comprise the entire population of the island at 1,065 inhabitants as of the 2000 census.

The village of Newtok, on the mainland across the Ningaluk River north of the island, is in the process of being moved to Nelson Island, due to erosion of the water table in the area where Newtok is currently located.

The natives are Yupiit, who maintain a predominantly traditional diet, fishing and hunting musk ox and caribou.

Nelson Island reported on the 1930 and 1940 U.S. Censuses as an unincorporated area (which included 5 villages on the 1940 census, including Nevortolemute, Nigtmuit (Nightmute), Pngortalick, Tanunak (Tununak), and Ukak.