| | Oak Grove, SC | McCormick, SC | United States |
| Population | 11,803 | 2,936 | 329,725,481 |
| Female Population | 51.7% | 37.4% | 50.5% |
| Male Population | 48.3% | 62.6% | 49.5% |
| Median Age | 37.9 | 42.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 10,479 | 2,772 | 309,327,143 |
| Population - 2000 | 8,183 | 1,489 | 285,036,114 |
| Population - 1990 | 6,989 | 1,659 | 251,960,433 |
| Pop. 2000 to Now | 36.7% | 55.8% | 15.6% |
| Pop. 1990 to Now | 60.1% | 39.8% | 30.8% |
| space4 | | | |
| Population Density | 1,836.2 | 724.6 | 93.4 |
| Land Area | 6.4 | 4.1 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Oak Grove, SC | McCormick, SC | United States |
| Age 0 to 4 | 5.3% | 4.8% | 5.9% |
| Age 5 to 9 | 6.5% | 3.7% | 6.1% |
| Age 10 to 14 | 4.7% | 7.7% | 6.6% |
| Age 15 to 17 | 4.1% | 3.0% | 3.9% |
| Age 18 to 20 | 2.0% | 1.4% | 4.0% |
| Age 21 to 24 | 2.5% | 3.4% | 5.2% |
| Age 25 to 34 | 19.0% | 14.1% | 13.8% |
| Age 35 to 44 | 14.3% | 15.1% | 12.9% |
| Age 45 to 54 | 11.0% | 15.3% | 12.6% |
| Age 55 to 59 | 7.2% | 9.1% | 6.7% |
| Age 60 to 64 | 7.0% | 9.4% | 6.3% |
| Age 65 to 74 | 9.8% | 7.3% | 9.6% |
| Age 75 to 84 | 4.3% | 3.5% | 4.5% |
| Age 85 and over | 2.1% | 2.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Oak Grove, SC | McCormick, SC | United States |
| White | 69.7% | 28.6% | 59.4% |
| Black | 15.3% | 66.6% | 12.2% |
| Asian | 1.6% | 0.1% | 5.6% |
| Native American | 0.7% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.3% | 0.0% | 0.4% |
| Two or More Races | 3.8% | 3.9% | 3.2% |
| Hispanic | 8.6% | 0.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Oak Grove, SC | McCormick, SC | United States |
| Married Population | 45.9% | 30.3% | 49.8% |
| Currently Married | 44.6% | 26.9% | 48.0% |
| Married but Separated | 1.4% | 3.4% | 1.8% |
| Single Population | 54.1% | 69.7% | 50.2% |
| Never Married | 35.3% | 46.4% | 33.8% |
| Divorced | 12.9% | 12.4% | 10.8% |
| Widowed | 5.9% | 10.9% | 5.6% |
| space5 | | | |
| Household Size | 2.34 | 2.54 | 2.60 |
| Households | 5,024 | 783 | 124,010,992 |
| Family Households | 3,035 | 459 | 80,755,759 |
| Married couple, w/children | 22.6% | 11.1% | 30.5% |
| Married couple, no children | 45.3% | 37.3% | 42.9% |
| Non Family Households | 1,989 | 324 | 43,255,233 |
| Single householder, w/children | 19.8% | 39.2% | 15.8% |
| Single householder, no children | 12.2% | 12.4% | 10.8% |