Tallahatchie County was organized 23 Dec 1833, from territory aquired by the US from the Choctaw tribe of Indians, at the Treaty of Dancing Rabbit in 1830. 1
Located eight miles east of Webb (a few miles west of Charleston), the land on this site was first purchased between 1835 and 1838; years later became known as Cowart for the owner of a local plantation. Cowart eventually sold the land in small tracts, and a man named Marshall bought a tract; building a store and filling station. The place was then known locally as: Marshall's Filling Station. 2
On 1 May 1908, the Y&MV (Yazoo & Mississippi Valley) Railroad opened a depot at the town of Cowart; later the line became part of the Illinois Central Railroad, which ran between Phillips and Charleston. The line was abandoned on 14 May 1964. 3
In a phone conversation with Kathrine Clark (of Tippo MS) on 1 Mar 1992; A car salesman named Dave Cowart, had a dealership in Cowart MS in the early 1920's. In the 1992 edition of Rand McNally Commercial Atlas & Marketing Guide, Cowart MS is located in H-6 on the map of Mississippi. It is considered a rural community, and receives its mail from nearby Charleston MS 38921.
I have been unable to find out who the Cowart was that the town was named for yet. I contacted Mississippi State University and Mississippi State Archives with no success.