The Naval Reserve Armory is a building in the South Lake Union neighborhood of Seattle, Washington, United States. It is a large concrete structure influenced by the Moderne and Art Deco movements, which was built by the Works Progress Administration from 1941-42. The main interior feature is a 133 x 100 ft (40.5 x 30 m) drill hall which was used by the U.S. Naval Reserve to train thousands of young recruits for service in World War II. The building is noted for its association with mass mobilization during the war as well as its involvement with Depression-era work relief.