| | Flat Rock, NC | Black Mountain, NC | United States |
| Population | 3,460 | 8,386 | 329,725,481 |
| Female Population | 52.3% | 59.7% | 50.5% |
| Male Population | 47.7% | 40.3% | 49.5% |
| Median Age | 63.1 | 57.5 | 38.4 |
| space3 | | | |
| Population - 2010 | 3,119 | 7,855 | 309,327,143 |
| Population - 2000 | 2,565 | 7,511 | 285,036,114 |
| Population - 1990 | 1,940 | 5,418 | 251,960,433 |
| Pop. 2000 to Now | 32.9% | 9.9% | 15.6% |
| Pop. 1990 to Now | 75.7% | 52.4% | 30.8% |
| space4 | | | |
| Population Density | 427.1 | 1,253.1 | 93.4 |
| Land Area | 8.1 | 6.7 | 3,531,905.4 |
| Water Area | 0.1 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Flat Rock, NC | Black Mountain, NC | United States |
| Age 0 to 4 | 2.1% | 5.2% | 5.9% |
| Age 5 to 9 | 2.9% | 6.7% | 6.1% |
| Age 10 to 14 | 4.1% | 1.8% | 6.6% |
| Age 15 to 17 | 0.8% | 1.2% | 3.9% |
| Age 18 to 20 | 1.4% | 0.4% | 4.0% |
| Age 21 to 24 | 1.6% | 2.1% | 5.2% |
| Age 25 to 34 | 5.1% | 7.3% | 13.8% |
| Age 35 to 44 | 6.3% | 12.0% | 12.9% |
| Age 45 to 54 | 9.0% | 10.9% | 12.6% |
| Age 55 to 59 | 9.4% | 4.5% | 6.7% |
| Age 60 to 64 | 8.7% | 10.0% | 6.3% |
| Age 65 to 74 | 27.6% | 15.4% | 9.6% |
| Age 75 to 84 | 17.7% | 11.5% | 4.5% |
| Age 85 and over | 3.3% | 10.9% | 1.9% |
| space1 | | | |
| Race | | | |
| | Flat Rock, NC | Black Mountain, NC | United States |
| White | 94.3% | 93.0% | 59.4% |
| Black | 0.0% | 1.7% | 12.2% |
| Asian | 0.0% | 0.1% | 5.6% |
| Native American | 0.0% | 0.3% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 1.3% | 0.4% |
| Two or More Races | 0.5% | 2.6% | 3.2% |
| Hispanic | 5.2% | 1.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Flat Rock, NC | Black Mountain, NC | United States |
| Married Population | 72.9% | 53.2% | 49.8% |
| Currently Married | 70.8% | 52.5% | 48.0% |
| Married but Separated | 2.2% | 0.7% | 1.8% |
| Single Population | 27.1% | 46.8% | 50.2% |
| Never Married | 11.6% | 22.5% | 33.8% |
| Divorced | 10.6% | 10.1% | 10.8% |
| Widowed | 5.0% | 14.2% | 5.6% |
| space5 | | | |
| Household Size | 2.07 | 2.08 | 2.60 |
| Households | 1,672 | 3,928 | 124,010,992 |
| Family Households | 1,140 | 2,177 | 80,755,759 |
| Married couple, w/children | 10.9% | 27.1% | 30.5% |
| Married couple, no children | 85.8% | 61.6% | 42.9% |
| Non Family Households | 532 | 1,751 | 43,255,233 |
| Single householder, w/children | 0.6% | 5.2% | 15.8% |
| Single householder, no children | 2.7% | 6.1% | 10.8% |