| | Jennings, FL | Madison, FL | United States |
| Population | 704 | 2,903 | 329,725,481 |
| Female Population | 56.5% | 48.5% | 50.5% |
| Male Population | 43.5% | 51.5% | 49.5% |
| Median Age | 30.4 | 34.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 867 | 3,030 | 309,327,143 |
| Population - 2000 | 833 | 3,061 | 285,036,114 |
| Population - 1990 | 712 | 3,345 | 251,960,433 |
| Pop. 2000 to Now | 4.3% | -8.9% | 15.6% |
| Pop. 1990 to Now | 22.1% | -16.6% | 30.8% |
| space4 | | | |
| Population Density | 264.7 | 1,101.3 | 93.4 |
| Land Area | 2.7 | 2.6 | 3,531,905.4 |
| Water Area | 0.0 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Jennings, FL | Madison, FL | United States |
| Age 0 to 4 | 9.4% | 7.8% | 5.9% |
| Age 5 to 9 | 7.0% | 5.3% | 6.1% |
| Age 10 to 14 | 14.3% | 5.4% | 6.6% |
| Age 15 to 17 | 9.8% | 4.1% | 3.9% |
| Age 18 to 20 | 1.7% | 5.0% | 4.0% |
| Age 21 to 24 | 0.6% | 7.5% | 5.2% |
| Age 25 to 34 | 17.3% | 15.8% | 13.8% |
| Age 35 to 44 | 4.8% | 11.4% | 12.9% |
| Age 45 to 54 | 10.8% | 12.9% | 12.6% |
| Age 55 to 59 | 4.4% | 5.2% | 6.7% |
| Age 60 to 64 | 1.1% | 2.4% | 6.3% |
| Age 65 to 74 | 12.1% | 10.5% | 9.6% |
| Age 75 to 84 | 4.3% | 4.6% | 4.5% |
| Age 85 and over | 2.4% | 2.2% | 1.9% |
| space1 | | | |
| Race | | | |
| | Jennings, FL | Madison, FL | United States |
| White | 39.6% | 37.6% | 59.4% |
| Black | 23.7% | 55.8% | 12.2% |
| Asian | 0.0% | 0.0% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.3% | 0.4% |
| Two or More Races | 0.0% | 2.9% | 3.2% |
| Hispanic | 36.6% | 3.3% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Jennings, FL | Madison, FL | United States |
| Married Population | 49.8% | 32.9% | 49.8% |
| Currently Married | 43.2% | 31.8% | 48.0% |
| Married but Separated | 6.6% | 1.1% | 1.8% |
| Single Population | 50.2% | 67.1% | 50.2% |
| Never Married | 38.1% | 48.6% | 33.8% |
| Divorced | 3.7% | 10.6% | 10.8% |
| Widowed | 8.4% | 7.9% | 5.6% |
| space5 | | | |
| Household Size | 2.89 | 2.52 | 2.60 |
| Households | 238 | 1,104 | 124,010,992 |
| Family Households | 171 | 557 | 80,755,759 |
| Married couple, w/children | 32.7% | 29.1% | 30.5% |
| Married couple, no children | 21.6% | 23.2% | 42.9% |
| Non Family Households | 67 | 547 | 43,255,233 |
| Single householder, w/children | 40.4% | 26.9% | 15.8% |
| Single householder, no children | 5.3% | 20.8% | 10.8% |