The .38 Long Colt, also known as .38 LC, is a black powder cartridge introduced by Colt's Manufacturing Company in 1875. In 1892, it was adopted as a standard military pistol cartridge by the United States Army for the Colt M1892 revolver. The metric designation for the .38 Long Colt is 9.1×26mm. It is slightly more powerful than the .38 Short Colt, also known as .38 SC. The original .38 SC and .38 LC differ in case length, bullet diameter, weight, and design and are not interchangeable; however, modern production .38 SC ammunition is now loaded with a smaller, internally-lubricated bullet which can be fired from firearms chambered in .38 LC or .38 Special. The modern .38 LC can be fired from a .38 Special firearm, but not from a firearm designed for the .38 SC, since the case length is too long.

Colt's Manufacturing Company, LLC is an American firearms manufacturer, founded in 1855 by Samuel Colt and now a subsidiary of Czech holding company Colt CZ Group. It is the successor corporation to Colt's earlier firearms-making efforts, which started in 1836. Colt is known for the engineering, production, and marketing of firearms, most especially between the 1850s and World War I, when it was a dominating force in its industry and a seminal influence on manufacturing technology. Colt's earliest designs played a major role in the popularization of the revolver and the shift away from single-shot pistols. Although Samuel Colt did not invent the revolver concept, his designs resulted in the first very successful model.