Farmington is on Farm Road 1417 ten miles south of Sherman in south central Grayson County. The first settlers arrived in the area in the mid-1840s. Community development occurred through the efforts of William W. Wheat, Henry Campbell, and Samuel C. Watson. A post office opened in 1861. By the end of the Civil War Farmington had established itself as a school and church community for area farmers. By 1885 it had three churches, a school, a general store, a cotton gin, and a gristmill. The population slowly increased over the next two decades, to peak of 171 in 1904. That year postal service ended, and over the next few decades the number of residents steadily declined. By the end of World War II Farmington had fifty residents, a church, a school, and a general store. The population was estimated at twenty from 1940 to 1990. In 2000 the population was thirty-eight.