Beaver is a city in, and county seat of, Beaver County in southwestern Utah, United States. The population was 3,592 at the 2020 census, u…Beaver is a city in, and county seat of, Beaver County in southwestern Utah, United States. The population was 3,592 at the 2020 census, up from the 2010 figure of 3,112. Indigenous peoples lived in the area for thousands of years, as demonstrated by archeological evidence. A number of identified prehistoric sites have been found in Beaver County, dating to the Archaic and Sevier Fremont periods. A prehistoric obsidian quarry site has been identified in the nearby Mineral Mountains.