Kokhanok 65 mi (105 km) NW Karluk 65 mi (104 km) SE Igiugig 71 mi (115 km) NW Larsen Bay 71 mi (115 km) SE Anchorage 250 mi (403 km) NE
This feature is part of the Savonoski River Cluster of volcanoes, as defined by Hildreth and others (2004) . From Hildreth and others (2004) : "Rainbow River Cone (Peak 3980) is a small basaltic volcano (51.8-53% SiO2) perched on a basement ridge east of Rainbow River, 15 km NW of Mount Denison. The glacially sculpted cone, 1 km wide with 330 m relief, consists of radially dipping stacks of thin lavas and breccia sheets intercalated with scoria falls, well exposed on bounding cliffs, cut by numerous dikes, and gutted by a northerly cirque. Lavas and ejecta contain phenocrysts of plagioclase, orthopyroxene, clinopyroxene, olivine, and Fe-Ti oxides. An ice-scoured lava plateau (390 +/- 39 ka) extends 1 km SE from the cone."