US Volcanoes

This map layer includes Holocene volcanoes, which are those thought to be active in the last 10,000 years, that are within an extended area of the northern hemisphere centered on the United States. The data are a subset of data available from the Global Volcanism Program, Smithsonian Institution at http://www.volcano.si.edu/.

Source:
National Atlas of the United States, 200404, Volcanoes: National Atlas of the United States, Reston, VA.
http://dds.cr.usgs.gov/pub/data/nationalatlas/volcanx020_nt00036.tar.gz