Owasco is an unincorporated community in Sullivan County, in the U.S. state of Missouri.
A post office called Owasco was established in 1858, and remained in operation until 1919. Owasco is an Indian name for "bridge". Bessides the post office, Owasco had a country store.
Coordinates: 40°08′17″N 92°58′41″W / 40.13806°N 92.97806°W