The Boulder Dam, officially known as the Hoover Dam, spans the Colorado River on the border between Arizona and Nevada. The dam was originally named after the Boulder Canyon, the dam's original location. However, the dam's location was moved to the Black Canyon and was instead named after former President Herbert Hoover. The names were used interchangeably until April 1947, when President Harry Truman approved a congressional resolution that officially confirmed the dam would carry Hoover’s name.
The Boulder Dam emerged in the early 20th century as a solution to Southewestern farmers' need for water. Initially, they attempted to do this by constructing a network of canals. However, the river broke through the canals in 1905, inadvertently creating the Saltone Sea.
The dam was first proposed in 1922 by U.S. Bureau of Reclamation director Arthur Powell Davis. He advocated the creation of a dam that would control flooding, provide irrigation, and generate and sell hydroelectric power. The initial project cost estimate of $165 million was offset by selling the power generated from the dam. The proposal stalled for several years due to disagreements among representatives from the seven affected states - Colorado, Wyoming, New Mexico, Arizona, Utah, Nevada and California - until President Calvin Coolidge approved it in 1928. Work began on the dam in 1931, and it was completed in 1935.