Farmington is a town in Whitman County, Washington, United States. The population was 146 at the 2010 census.
Farmington was first settled in 1871, and was founded and named by G.W.Truax in 1878. Farmington was officially incorporated in 1888. At Farmington's peak (1900–1930) the town boasted a population of just under 500. As demand for farm labor decreased, the population and business of the town decreased. Today, Farmington has a population of about 150.
Farmington is located at 47°5′26″N 117°2′47″W / 47.09056°N 117.04639°W / 47.09056; -117.04639 (47.090501, -117.046505).