Camp Haan was a US Army training camp built in 1940, near March Air Force Base in Riverside County, California Camp Haan was opened in January 1941 as a training camp for Coast Artillery Antiaircraft gunners. The 8,058 acres camp was about four miles by three miles with tent housing. The camp was named after Major General William George Haan of World War I. By the end of 1941, the camp had a wood service building, 28 miles of streets, five chapels, and a hospital. The first troops trained were sent for the defense of Los Angeles and San Francisco. The Attack on Pearl Harbor and the Battle of Los Angeles–Bombardment of Ellwood had put all of California on high alert. The Army Service Depot was added to the camp in March 1942. The site of the former Camp Haan is next to California Interstate 215 at the Van Buren Boulevard exit.