| | Westmoreland, TN | Castalian Springs, TN | United States |
| Population | 2,666 | 562 | 329,725,481 |
| Female Population | 54.2% | 45.0% | 50.5% |
| Male Population | 45.8% | 55.0% | 49.5% |
| Median Age | 36 | 46.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 2,342 | 340 | 309,327,143 |
| Population - 2000 | 2,093 | 418 | 285,036,114 |
| Population - 1990 | 1,726 | 313 | 251,960,433 |
| Pop. 2000 to Now | 16.1% | 45.2% | 15.6% |
| Pop. 1990 to Now | 40.7% | 93.9% | 30.8% |
| space4 | | | |
| Population Density | 637.8 | 96.6 | 93.4 |
| Land Area | 4.2 | 5.8 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Westmoreland, TN | Castalian Springs, TN | United States |
| Age 0 to 4 | 9.2% | 5.7% | 5.9% |
| Age 5 to 9 | 6.8% | 9.4% | 6.1% |
| Age 10 to 14 | 7.1% | 6.8% | 6.6% |
| Age 15 to 17 | 5.9% | 3.4% | 3.9% |
| Age 18 to 20 | 4.0% | 1.4% | 4.0% |
| Age 21 to 24 | 4.0% | 6.2% | 5.2% |
| Age 25 to 34 | 12.4% | 7.7% | 13.8% |
| Age 35 to 44 | 16.0% | 8.9% | 12.9% |
| Age 45 to 54 | 8.9% | 18.5% | 12.6% |
| Age 55 to 59 | 5.3% | 7.8% | 6.7% |
| Age 60 to 64 | 7.2% | 7.7% | 6.3% |
| Age 65 to 74 | 7.1% | 8.7% | 9.6% |
| Age 75 to 84 | 4.2% | 7.8% | 4.5% |
| Age 85 and over | 2.2% | 0.0% | 1.9% |
| space1 | | | |
| Race | | | |
| | Westmoreland, TN | Castalian Springs, TN | United States |
| White | 92.5% | 97.5% | 59.4% |
| Black | 0.2% | 0.0% | 12.2% |
| Asian | 0.0% | 0.0% | 5.6% |
| Native American | 0.6% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.2% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 4.4% | 2.5% | 3.2% |
| Hispanic | 2.1% | 0.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Westmoreland, TN | Castalian Springs, TN | United States |
| Married Population | 50.0% | 67.7% | 49.8% |
| Currently Married | 48.1% | 64.7% | 48.0% |
| Married but Separated | 1.9% | 3.0% | 1.8% |
| Single Population | 50.0% | 32.3% | 50.2% |
| Never Married | 26.0% | 15.7% | 33.8% |
| Divorced | 16.2% | 14.1% | 10.8% |
| Widowed | 7.8% | 2.5% | 5.6% |
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| Household Size | 2.83 | 2.76 | 2.60 |
| Households | 905 | 202 | 124,010,992 |
| Family Households | 627 | 136 | 80,755,759 |
| Married couple, w/children | 45.3% | 50.7% | 30.5% |
| Married couple, no children | 27.1% | 36.8% | 42.9% |
| Non Family Households | 278 | 66 | 43,255,233 |
| Single householder, w/children | 20.9% | 8.1% | 15.8% |
| Single householder, no children | 6.7% | 4.4% | 10.8% |