city, Clark county, southeastern Nevada, U.S., overlooking Lake Mead, which is impounded by the Hoover Dam. Lying above the deep, narrow Black and Boulder canyons of the Colorado River on the Nevada-Arizona border, it was established in 1931 by the federal government as a residential community for personnel employed at Hoover (Boulder) Dam and other local construction projects, including Lake Mohave and Davis Dam. From 1931 to 1935, during the construction of the Hoover Dam, Boulder City housed more than 4,000 workers in 1,500 buildings. After the dam was completed most of the workers left, and Boulder City became a federally administered headquarters for several agencies involved in the dam's operation. In 1958 the federal government ceded the townsite, then about 33 square miles (85 square km), to Boulder City's residents. The city charter, approved by voters in 1960, prohibits gambling. In 1979 the city government approved a referendum to control growth, and Boulder City has since limited the number of building permits issued each year; its population grew at a rate of only 3 percent annually in the 1990s, a rate far lower than that of other Nevada municipalities. Boulder City is headquarters for the U.S. Water and Power Resources Service and for the Lake Mead National Recreational Area. Inc. 1960. Pop. (1990) 12,567; (2000) 14,966.