Basalt Rock Company was a multifaceted industrial operation that was founded in 1920. The company started as a rock quarrying operation located a few miles south of Napa, California near the Napa River. It later branched out into the ship building business in 1941 when it started building ships for the U.S. Navy for use during World War II. Following the war, the plant built 30 miles of pipe for the City of Napa's pipeline from Lake Hennessey.