Marshall County is a county located in the U.S. state of Mississippi. In 2010, the population was 37,144. Its county seat is Holly Springs. Marshall County is named for Chief Justice of the United States John Marshall.

Marshall County is part of the Memphis, TN–MS–AR Metropolitan Statistical Area.

According to the 2000 census, the county has a total area of 709.80 square miles (1,838.4 km²), of which 706.33 square miles (1,829.4 km²) (or 99.51%) is land and 3.47 square miles (9.0 km²) (or 0.49%) is water.

At the 2000 census, there were 34,993 people, 12,163 households and 9,110 families residing in the county. The population density was 50 per square mile (19/km²). There were 13,252 housing units at an average density of 19 per square mile (7/km²). The racial makeup of the county was 48.37% White, 50.36% Black or African American, 0.17% Native American, 0.11% Asian, 0.01% Pacific Islander, 0.37% from other races, and 0.62% from two or more races. 1.21% of the population were Hispanic or Latino of any race.

Mississippi (ⁱ/ˌmɪsɨˈsɪpi/) is a U.S. state located in the Southern United States. Jackson is the state capital and largest city. The name of the state derives from the Mississippi River, which flows along its western boundary, whose name comes from the Ojibwe word misi-ziibi ("Great River"). Mississippi is the 32nd most extensive and the 31st most populous of the 50 United States. The state is heavily forested outside of the Mississippi Delta area, which was cleared for cotton cultivation in the 19th century. Today, its catfish aquaculture farms produce the majority of farm-raised catfish consumed in the United States. The state symbol is the magnolia grandiflora tree.

Mississippi is bordered on the north by Tennessee, on the east by Alabama, on the south by Louisiana and a narrow coast on the Gulf of Mexico and on the west, across the Mississippi River, by Louisiana and Arkansas.

In addition to its namesake, major rivers in Mississippi include the Big Black River, the Pearl River, the Yazoo River, the Pascagoula River, and the Tombigbee River. Major lakes include Ross Barnett Reservoir, Arkabutla Lake, Sardis Lake and Grenada Lake. The largest lake in Mississippi is Grenada Lake.

Marshall County is the name of twelve counties in the United States: