Costonia is an unincorporated community in Jefferson County, in the U.S. state of Ohio. [1]
A post office called Costonia was established in 1897, and remained in operation until 1937. [2] Besides the post office, Costonia had a country store. [3]
40°25′37″N 80°37′04″W / 40.42694°N 80.61778°W