Upon the death of American silent film actor William S. Hart in 1946, he bequeathed his ranch and home to Los Angeles County so that it could be converted into a park and museum.

[1] Since 2015, the park has been home to the Santa Clarita Cowboy Festival and Annual Hart of the West Powwow.

[2] On July 12, 2022, the Los Angeles County Board of Supervisors and City of Santa Clarita entered negotiations in order to transfer ownership of William S. Hart Regional Park and the William S. Hart Museum from the Natural History Museum of Los Angeles County to the City of Santa Clarita.

[3] Since 2021, the Education and Cultural Learning Department of the Fernandeño Tataviam Band of Mission Indians government have partnered with the William S. Hart Museum to host the annual Traveling Tataveaveat: Acorn Harvest museum program.

The event educates the public on the indigenous history of the Santa Clarita Valley while demonstrating traditional methods of harvesting and processing the acorns of coast live oak into acorn flour.