The Union Oil Company Building in Santa Paula, California, is the birthplace of the Union Oil Company, organized there on October 17, 1890, above a hardware store and post office. After Union Oil moved its headquarters to Los Angeles in 1900, the building remained in use as a field division office. Its importance rests on both its central place in California oil history and its preservation as a museum. It became the Union Oil Museum in 1950, was restored and reopened as the California Oil Museum in 1990, and continues to interpret the state’s petroleum industry through historic equipment, recreated interiors, and preserved artifacts.