Farmington is a town in Whitman County, Washington, United States. Take a look below for 10 awesome and fascinating facts about Farmington, Washington, United States. 1. The population was 146 at the 2010 census. 2. Farmington was laid out in 1878. 3. Farmington was officially incorporated in 1888. At Farmington’s peak (1900–1930) the town boasted…