In 1911, the Turlock Melon Carnival took place for the first time, sponsored by the Turlock Chamber of Commerce. The Turlock Melon Carnival was an effort to promote and market the local melon industry and shipping business.  A group of musicians organized to become the Melon City Band.

The Melon Carnival lasted only a few years, and in 1924, the American Legion Rex Ish Post 88 organized a 4th of July celebration for largely the same purpose. In 1925, the American Legion resurrected the name “Turlock Melon Carnival” for the mid-summer festival.

The 4-H and FFA livestock shows were instituted in 1933, and in 1935, the State of California issued a charter that established the 38th District Agriculture Association (DAA), which remains today. The “fair” was run jointly by the American Legion post and the DAA until 1944 when the American Legion sold the site and buildings to the DAA, which has had the sole responsibility for its operation ever since.

No fairs were held during World War II, although the carnivals and horse pulling events continued in the downtown area. The fair was used as a Relocation Center for Japanese-Americans in 1942 and a Rehabilitation Center for the U.S. Army Ninth Service Command from 1943 to 1946. The fair resumed operation after the war, and in 1956, the name “Stanislaus County Fair” was used for the first time on the marquee. In 1960, the fairgrounds became the original home of California State University, Stanislaus.

From a summer weekend in 1911 to a 10-day run, the Stanislaus County Fair has been a source of fun, entertainment and education for people of all ages. A record 261,089 people attended the 1989 Fair.

On March 15, 1999, the Stanislaus County Fair Board of Directors of the 38th District Agricultural Association with support from the Turlock American Legion resolved that the Stanislaus County Fair Arch Gate be recognized as a California State Point of Historical Interest. A marker was unveiled during an opening night ceremony during the 1999 Fair and is on public view just inside the historic Arch Gate.

The Stanislaus County Fair celebrated its centennial fair in 2011. Over 245, 000 people attended to honor this landmark occasion.