Sine-Saloum is a region in Senegal located north of the Gambia and south of the Petite Côte. It encompasses an area of 24,000 square kilometers, about 12% of Senegal, with a population in the 1990s of 1,060,000. The western portion contains the Saloum Delta, a river delta at the junction of the Saloum and the North Atlantic. It is in this region that the Saloum Delta National Park is located. 145,811 hectares of the Delta were designated a UNESCO Heritage Site in 2011. Because it flows so slowly, this delta allows saltwater to travel deep inland. Long ago, the Serer kingdoms of Sine and Saloum were rivals. In 1984, the area was divided into two administrative regions: Kaolack and Fatick.