| | Millbrook, AL | Huntsville, AL | United States |
| Population | 16,675 | 210,081 | 329,725,481 |
| Female Population | 55.4% | 51.3% | 50.5% |
| Male Population | 44.6% | 48.7% | 49.5% |
| Median Age | 35.8 | 37.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 15,064 | 180,926 | 309,327,143 |
| Population - 2000 | 10,386 | 158,216 | 285,036,114 |
| Population - 1990 | 6,050 | 159,789 | 251,960,433 |
| Pop. 2000 to Now | 55.2% | 28.3% | 15.6% |
| Pop. 1990 to Now | 166.4% | 27.0% | 30.8% |
| space4 | | | |
| Population Density | 1,274.8 | 980.1 | 93.4 |
| Land Area | 13.1 | 214.4 | 3,531,905.4 |
| Water Area | 0.3 | 1.4 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Millbrook, AL | Huntsville, AL | United States |
| Age 0 to 4 | 5.8% | 5.8% | 5.9% |
| Age 5 to 9 | 8.2% | 5.7% | 6.1% |
| Age 10 to 14 | 7.1% | 5.4% | 6.6% |
| Age 15 to 17 | 3.4% | 2.9% | 3.9% |
| Age 18 to 20 | 3.3% | 4.8% | 4.0% |
| Age 21 to 24 | 8.2% | 7.1% | 5.2% |
| Age 25 to 34 | 12.8% | 15.5% | 13.8% |
| Age 35 to 44 | 12.7% | 12.1% | 12.9% |
| Age 45 to 54 | 12.3% | 11.5% | 12.6% |
| Age 55 to 59 | 6.6% | 6.8% | 6.7% |
| Age 60 to 64 | 5.9% | 6.2% | 6.3% |
| Age 65 to 74 | 7.2% | 9.3% | 9.6% |
| Age 75 to 84 | 5.5% | 4.8% | 4.5% |
| Age 85 and over | 0.9% | 2.1% | 1.9% |
| space1 | | | |
| Race | | | |
| | Millbrook, AL | Huntsville, AL | United States |
| White | 63.0% | 57.0% | 59.4% |
| Black | 27.0% | 30.6% | 12.2% |
| Asian | 2.2% | 2.2% | 5.6% |
| Native American | 0.1% | 0.3% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.1% | 0.2% |
| Other | 0.0% | 0.1% | 0.4% |
| Two or More Races | 2.9% | 3.3% | 3.2% |
| Hispanic | 4.9% | 6.4% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Millbrook, AL | Huntsville, AL | United States |
| Married Population | 50.2% | 45.7% | 49.8% |
| Currently Married | 47.9% | 43.6% | 48.0% |
| Married but Separated | 2.4% | 2.1% | 1.8% |
| Single Population | 49.8% | 54.3% | 50.2% |
| Never Married | 30.6% | 36.1% | 33.8% |
| Divorced | 11.0% | 12.4% | 10.8% |
| Widowed | 8.1% | 5.9% | 5.6% |
| space5 | | | |
| Household Size | 2.60 | 2.21 | 2.60 |
| Households | 6,420 | 91,048 | 124,010,992 |
| Family Households | 4,450 | 51,704 | 80,755,759 |
| Married couple, w/children | 24.9% | 23.3% | 30.5% |
| Married couple, no children | 39.2% | 45.6% | 42.9% |
| Non Family Households | 1,970 | 39,344 | 43,255,233 |
| Single householder, w/children | 23.7% | 19.0% | 15.8% |
| Single householder, no children | 12.2% | 12.1% | 10.8% |