The M115 203 mm howitzer, also known as the M115 8 inch howitzer, was a towed howitzer used by the United States Army. Originally designated the 8 inch Howitzer M1, it was designed during the buildup to World War II as a counterpart to the German 17 cm K 18 gun. The M115 could be towed by the M35 Prime Mover gun tractor or a large truck.

The M115 owes some of its origins to the British BL 8 inch Howitzer of the First World War, using the same Welin screw for the breech. The carriage was the same as used for the US 155 mm gun, and was also adopted by the British for their 7.2 inch Mark 6 howitzer.

The M115 saw service in World War II, the Korean War, the Vietnam War, and the Croatia War. In NATO service, its main purpose was to fire nuclear rounds, which have since been discontinued. The M115 was removed from service due to its short range, because the nuclear round yield exceeded the range of the weapon.

US Government Archive number for this historic video is:
111 TF 3646 INSK/DNT