Springfield Armory Museum, Massachusetts

The Springfield Armory, now a National Historic Site, was the design and manufacturing site for numerous small arms, including muskets, the M-1 Garand rifle, the M-16 rifle, and machine guns. It is a 55-acre historic industrial complex now operated by the National Park Service, as the armory closed in 1968, after almost 200 years of operation. The museum claims to hold the "world's largest collection of U.S. military small arms."