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.

The Saluda River is a principal tributary of the Congaree River, about 200 mi (320 km) long, in northern and western South Carolina in the United States. Via the Congaree River, it is part of the watershed of the Santee River, which flows to the Atlantic Ocean.