The Kelly Plow Company, the only full-line plow factory in the Southwest, began in 1843, when John A. Stewart began making crude plows in a shop operated by a man named Sanders near Marshall, Texas. In 1848 Stewart moved his plow patterns to Four Mile Branch, a popular campsite for wagoners, four miles west of Jefferson, Texas. Stewart and his brother-in-law, Zachariah Lockett, made plows and operated a general repair shop, where they melted iron in a pocket furnace heated by charcoal. George Addison Kelly joined the company in 1852. The firm became Kelly and Stewart in 1858, when it erected a larger building and added cast-iron stoves, cooking utensils, machinery castings, and andirons to its products. Kelly bought full ownership in 1860, the same year that he developed the Blue Kelly Plow, which later became so widely used in Texas that "Kelly" became a household word and "Blue Kelly" was synonymous with plow.
During the Civil War the Kelly Plow Company was a part of the arsenal for the Confederacy. It turned out plows, civilian utensils, and cast-iron cannonballs. It produced a new "pony plow" during Reconstruction. By 1866 the enlarged business began to manufacture its own iron by smelting East Texas ores in a furnace two miles west of Kellyville. The coming of railroads and the decline of Jefferson as a commercial center decreased the value of Kellyville as a factory location. The plant burned in 1880, and Kelly transferred the salvage to Longview in 1882. General agricultural implements were added to the line of products in 1882, and in 1907 the plant produced a full line of steel plows and tillage implements.
After George Kelly died in 1909, Robert Marvin Kelly succeeded him as president. LeGrand D. Kelly, another son, was comanager and secretary-treasurer until his death in 1941. George A. Kelly, Jr., and LeGrand D. Kelly, Jr., managed the business in 1945. For a century the one-family business supplied plow tools to five generations of Texas farmers. In 1950 the third generation of the Kelly family continued to own and manage the Kelly Plow Company, which had never solicited outside financing. The company seems to have stopped manufacturing plows by the 1960s. As late as the 1970s George A. Kelly, Jr., was engaged in banking and investing activities and used the name Kelly Plow Company to refer to his investment company.