Nelson Lagoon is a census-designated place (CDP) in Aleutians East Borough, Alaska, United States. At the 2020 census the population was 41, down from 52 in 2010 and 83 in 2000.

Aleutians East Borough is a 2nd class borough in the U.S. state of Alaska. As of the 2020 census the borough's population was 3,420. The borough seat is Sand Point.