The area remained very rural until the coming of the Odakyu Electric Railway in 1927 and the Sagami Railway in 1935, which spurred development, but the area was mostly farmland when the Imperial Japanese Army Academy relocated to the Zama area in 1937. The increase in population led Zama Village to be promoted to Zama town the same year. However, in 1941, Zama Town and surrounding villages were merged into Sagamihara. In 1944, the Kōza Naval Arsenal of the Imperial Japanese Navy was established in the area. It was closed with the end of World War II, and the Imperial Japanese Army Academy was turned over to the United States Army to become Camp Zama.