| | Southlake, TX | Whitefish, MT | United States |
| Population | 30,754 | 7,783 | 329,725,481 |
| Female Population | 50.4% | 50.6% | 50.5% |
| Male Population | 49.6% | 49.4% | 49.5% |
| Median Age | 42 | 40.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 26,662 | 6,505 | 309,327,143 |
| Population - 2000 | 21,519 | 5,032 | 285,036,114 |
| Population - 1990 | 7,065 | 4,368 | 251,960,433 |
| Pop. 2000 to Now | 50.0% | 73.2% | 15.6% |
| Pop. 1990 to Now | 356.9% | 99.5% | 30.8% |
| space4 | | | |
| Population Density | 1,408.7 | 1,168.8 | 93.4 |
| Land Area | 21.8 | 6.7 | 3,531,905.4 |
| Water Area | 0.6 | 5.4 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Southlake, TX | Whitefish, MT | United States |
| Age 0 to 4 | 5.2% | 5.0% | 5.9% |
| Age 5 to 9 | 8.3% | 6.2% | 6.1% |
| Age 10 to 14 | 12.8% | 4.4% | 6.6% |
| Age 15 to 17 | 6.9% | 2.9% | 3.9% |
| Age 18 to 20 | 2.3% | 1.2% | 4.0% |
| Age 21 to 24 | 2.0% | 3.3% | 5.2% |
| Age 25 to 34 | 4.0% | 17.6% | 13.8% |
| Age 35 to 44 | 13.6% | 16.2% | 12.9% |
| Age 45 to 54 | 19.3% | 10.8% | 12.6% |
| Age 55 to 59 | 8.0% | 7.2% | 6.7% |
| Age 60 to 64 | 6.5% | 6.7% | 6.3% |
| Age 65 to 74 | 7.3% | 10.4% | 9.6% |
| Age 75 to 84 | 2.5% | 6.9% | 4.5% |
| Age 85 and over | 1.4% | 1.5% | 1.9% |
| space1 | | | |
| Race | | | |
| | Southlake, TX | Whitefish, MT | United States |
| White | 72.2% | 95.0% | 59.4% |
| Black | 0.8% | 0.0% | 12.2% |
| Asian | 17.3% | 0.0% | 5.6% |
| Native American | 0.1% | 0.6% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.1% | 0.1% | 0.4% |
| Two or More Races | 2.5% | 2.6% | 3.2% |
| Hispanic | 7.0% | 1.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Southlake, TX | Whitefish, MT | United States |
| Married Population | 73.7% | 49.6% | 49.8% |
| Currently Married | 73.1% | 48.4% | 48.0% |
| Married but Separated | 0.6% | 1.1% | 1.8% |
| Single Population | 26.3% | 50.4% | 50.2% |
| Never Married | 18.7% | 29.8% | 33.8% |
| Divorced | 3.9% | 14.7% | 10.8% |
| Widowed | 3.8% | 5.9% | 5.6% |
| space5 | | | |
| Household Size | 3.30 | 2.21 | 2.60 |
| Households | 9,299 | 3,475 | 124,010,992 |
| Family Households | 8,465 | 1,842 | 80,755,759 |
| Married couple, w/children | 53.3% | 35.2% | 30.5% |
| Married couple, no children | 39.3% | 47.1% | 42.9% |
| Non Family Households | 834 | 1,633 | 43,255,233 |
| Single householder, w/children | 3.8% | 8.4% | 15.8% |
| Single householder, no children | 3.7% | 9.3% | 10.8% |