Pioneer Union Elementary School District is a public school district in Hanford, California, United States.
The Pioneer district is one of the oldest in the area. According to records at the Hanford Carnegie Museum, Pioneer School was started on Aug. 5, 1870. Back then, it was a two-story building with a belfry. Pioneer originally served the rural area of Grangeville, but now serves from the edge of Lemoore to Hanford.