The 155 mm gun M1 was a 155 millimeter caliber field gun developed and used by the United States military. Nicknamed "Long Tom" (an appellation with a long and storied history in U.S. field and naval artillery), it was produced in M1 and M2 variants, later known as the M59. Developed to replace the Canon de 155mm GPF, the gun was deployed as a heavy field weapon and used during World War II and the Korean War, and also classed as secondary armament for seacoast defense. The gun could fire a 100 lb (45 kg) shell to a maximum range of 14 mi (23 km), with an estimated accuracy life of 1,500 rounds.
The Long Tom was also adopted by a number of other nations, including the United Kingdom, Austria, Israel, and the Netherlands.