Keystone is a city in McDowell County, West Virginia, United States. Per the 2020 census, the population was 176. Keystone is one of the few municipalities in West Virginia with an African-American majority, with 65 percent of the residents being black. The term "Free State of McDowell" was coined by Matthew Thomas Whittico, a local newspaper editor and community leader from Keystone in the early 20th century.