Slater-Marietta is a census-designated place (CDP) in Greenville County, South Carolina, United States, along the North Saluda River. At the 2000 census, there were 2,228 people. At the 2010 census, there were 2,176. At the 2020 census, there were 1,873. It is part of the Greenville–Mauldin–Easley Metropolitan Statistical Area.