Stepovak Bay is framed by the Stepovak Bay group of volcanoes, a chain of 5 cinder cone volcanoes in the Aleutian Arc. The volcanoes include Mount Kupreanof and four numbered volcanoes (Stepovak Bay 1, 2, 3, & 4). Mount Kupreanof and Stepovak Bay 2 and 4 erupted within the last 10,000 years, while Stepovak Bay 1 and 3 erupted before this, sometime in the Late Pleistocene. Mount Kupreanof's most recent eruption was possibly in March 1987.