Herbert Island (Aleut: Chiĝulax̂) is an island in the Islands of Four Mountains subgroup of the Aleutian archipelago. It is 3.1 miles (5.0 km) from Chuginadak Island, separated by the Chuginadak Pass. Yunaska Island is 16 miles (26 km) southeast of Herbert Island. Measuring 6.2 miles (10.0 km) across, Herbert Island is somewhat circular in shape and is covered by the 4,200 feet (1,300 m) Herbert Volcano, whose two km wide caldera is one of the largest in the Aleutian Islands.