The Ingakslugwat Hills consist of at least 32 small cinder cones and eight larger craters covering more than 500 km2 in the Yukon-Kuskokwin delta area of SW Alaska. Numerous small spatter cones and cinder cones range from 8 to 190 m in height; many are concentrated in the NW side of the volcanic field. The latest activity was considered to have occurred during the Holocene (Moll-Stalcup, in Wood and Kienle, 1990). One low cone containing a 400-m-wide lake may be a maar. This dominantly alkali olivine basaltic field also contains basanitic and nephelinitic rocks, some with inclusions of lherzolite and layered gabbro.