The Ingakslugwat Hills volcanic field is in the Yukon-Kuskokwim Delta in western Alaska. It contains eight large craters and about thirty small pyroclastic cones in an area of some 500 km2. The field contains unusual so-called Ingakslugwat volcanoes, volcanic ridges up to long and high which are formed by pyroclastic material. They most likely formed by the interaction of permafrost with magma, seeing as they have a hydrovolcanic nature despite being high above the water table.