Farmington is a city in St. Francois County located 60 miles (97 km) 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.