in Yukon River E of Pearl I., 23 mi. NE of Russian Mission, Yukon-Kuskokwim Delta. 4 miles long.
So named in 1916 by S. S. Post, U.S. Geological Survey (USGS), because a triangulation check base was established on this island.
Ingregamiut,
Para Point, Peters Point,
Base Island, Pearl Island,
Tuckers Slough,
Mountain Creek,