The U.S. Geological Survey (USGS) has issued an updated national volcanic threat assessment to identify U.S. volcanoes in need of research, monitoring, and mitigation efforts based on objective measures of volcano hazards and exposure of people and infrastructure to those hazards. Compared to the previous national volcanic threat assessment that was published in 2005 (which was also the first), the current assessment has added seven and removed 20 volcanoes. The assessment now consists of a total of 161 volcanoes, which are primarily concentrated in the western U.S., as well as in Alaska, Hawaii, the Northern Mariana Islands, and American Samoa. Additionally, USGS’s assessments place volcanoes into five threat categories, and with the present assessment some volcanoes moved between categories.