Holtville is a city in Imperial County, California. Holtville is located 10.5 miles east of El Centro. The population was 5,939 at the 2010 census, up from 5,612 in 2000. The city was founded in the 1880s by Swiss-German settlers, many of whom entered from Mexico. The construction of railroads in the 1890s, the All-American Canal in the late 1940s, and U.S. Route 80 in the 1920s and the North American Free Trade Agreement economic boom in the 1990s brought more people to Holtville and the Imperial Valley.