Seneca is a city in Oconee County, South Carolina, United States. The population was 7,652 at the 2000 census. It is the principal city of the Seneca Micropolitan Statistical Area, an which includes all of Oconee County and which is further included in the greater Greenville-Spartanburg-Anderson, South Carolina Combined Statistical Area. Seneca apartments for rent comparison page shows most up to date rent information on Seneca apartments and houses. Rent information is obtained from multiple rental sources but we cannot guarantee their accuracy.