Blackwell is an unincorporated community in a small part of Washington County and the extreme northern section of St. Francois County, Missouri, United States. It is located approximately seven and a half miles south of De Soto.
A variant name was "Blackwell Station". A post office called Blackwells Station was established in 1858, and the name was changed to Blackwell in 1885.[1] The community has the name of Lavinia Blackwell and Margaret Blackwell, first settlers.[2]