Farmington is a city in St. Francois County located south of St. Louis in the Lead Belt region in Missouri in the United States. As of the 2010 census, the population was 16,240. It is the county seat of St. Francois County. The Farmington Micropolitan Statistical Area includes St. Francois County and Washington County and has a population of 90,554 as of 2010. Farmington is a component of the St. Louis-St. Charles-Farmington, MO-IL Combined Statistical Area, also known as Greater St. Louis.
Farmington was established in 1822 after its agricultural history and was previously known as Murphy's Settlement for William Murphy of Kentucky who first visited the site in 1798. When St. Francois County was organized, the town was briefly called St. Francois Court House and then later renamed to Farmington.