San Manuel is a census-designated place in Pinal County, Arizona, United States. The population was 3,551 at the 2010 census.San Manuel was built in 1953 by Del E. Webb Construction Company as a company town to serve the then-new San Manuel copper mine, mill and smelter complex. When copper prices fell in the late 1990s, Broken Hill Proprietary, the owner of the mine and smelter complex shuttered both operations in June 1999. The closing saw 2,500 people lose their jobs. The mine and smelter were permanently closed in 2003.The town is on the edge of the Sonoran Desert and overlooks the San Pedro River valley and panoramic Galiuro Mountains. Today San Manuel is a destination for leisure, hunting, backroad travel and ATV's and is a gateway city of The Arizona Trail. Nearby towns are Oracle and Mammoth. Both are within 10 mi of San Manuel and make up a tri-community area.