Plain is a small unincorporated community in Chelan County, Washington, United States. It is located east of Coles Corner, Washington, near U.S. Route 2 and SR 207. Plain was serviced by the former SR 209, now called the Chumstick Highway, which connects Plain with Chumstick and Leavenworth along an old railroad grade. A post office called Plain was established in 1913, and remained in operation until 1936.