On N shore of Bristol Bay at the entrance to Togiak Bay, 19 mi. SW of Togiak, Kilbuck-Kuskokwim Mountains. 24 miles long.
Named for Captain Leontius Vasilevich Hagemeister, who was in command of three voyages to the Russian American colony and around the world; 1806-07 on the Neva, 1816-19 on the Kutuzov, and in 1828-30 on the Krothoy. The name was erroneously published as "Os(trov) Gagemeister" by Lieutenant Sarichev (1826, map 3).