The 2014 Santee, South Carolina, population is 946. There are 448 people per square mile (population density). The median age is 27.9. The US median is 37.2. 46.34% of people in Santee, South Carolina, are married. 4.51% are divorced. The average household size is 2.76 people. 17.48% of people are married, with children. 35.92% have children, but are single. 20.72% of people are white, 51.16% are black, 0.95% are asian, 0.00% are native american, and 21.14% claim 'Other'.