The Modesto Irrigation District (MID) is a special-purpose district that provides irrigation and drinking water, and electrical service, to customers in the San Joaquin Valley within Stanislaus County, California.

After a long delay caused by legal battles, the district finally started providing irrigation water in 1903.

San Francisco needed more drinking water, and the two districts wanted to continue exclusive use of the river.

Despite opposition from John Muir and the Sierra Club, San Francisco ultimately prevailed with the passing of the Raker Act, which authorized construction of the O'Shaughnessy Dam on the Tuolumne River, and eventually turned the Hetch Hetchy Valley into the Hetch Hetchy Reservoir.

By 1940, San Francisco and the two districts had become allies to develop the Tuolumne River watershed as a source of water and electricity.