| | Karnes City, TX | Brownwood, TX | United States |
| Population | 3,271 | 18,865 | 329,725,481 |
| Female Population | 44.5% | 51.0% | 50.5% |
| Male Population | 55.5% | 49.0% | 49.5% |
| Median Age | 33.6 | 35.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 3,076 | 19,269 | 309,327,143 |
| Population - 2000 | 3,457 | 18,813 | 285,036,114 |
| Population - 1990 | 2,916 | 18,387 | 251,960,433 |
| Pop. 2000 to Now | -1.5% | -3.2% | 15.6% |
| Pop. 1990 to Now | 16.8% | -1.0% | 30.8% |
| space4 | | | |
| Population Density | 1,446.7 | 1,275.4 | 93.4 |
| Land Area | 2.3 | 14.8 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Karnes City, TX | Brownwood, TX | United States |
| Age 0 to 4 | 3.4% | 6.4% | 5.9% |
| Age 5 to 9 | 6.7% | 5.3% | 6.1% |
| Age 10 to 14 | 6.4% | 6.5% | 6.6% |
| Age 15 to 17 | 2.9% | 5.4% | 3.9% |
| Age 18 to 20 | 4.5% | 5.1% | 4.0% |
| Age 21 to 24 | 9.4% | 6.8% | 5.2% |
| Age 25 to 34 | 19.5% | 14.0% | 13.8% |
| Age 35 to 44 | 14.9% | 11.9% | 12.9% |
| Age 45 to 54 | 14.9% | 11.2% | 12.6% |
| Age 55 to 59 | 5.7% | 5.9% | 6.7% |
| Age 60 to 64 | 4.1% | 6.0% | 6.3% |
| Age 65 to 74 | 4.4% | 8.3% | 9.6% |
| Age 75 to 84 | 1.6% | 4.6% | 4.5% |
| Age 85 and over | 1.7% | 2.6% | 1.9% |
| space1 | | | |
| Race | | | |
| | Karnes City, TX | Brownwood, TX | United States |
| White | 21.1% | 62.6% | 59.4% |
| Black | 5.4% | 5.0% | 12.2% |
| Asian | 0.1% | 0.4% | 5.6% |
| Native American | 0.2% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.4% | 0.4% |
| Two or More Races | 2.0% | 1.0% | 3.2% |
| Hispanic | 71.1% | 30.5% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Karnes City, TX | Brownwood, TX | United States |
| Married Population | 39.9% | 47.5% | 49.8% |
| Currently Married | 33.7% | 45.6% | 48.0% |
| Married but Separated | 6.2% | 1.9% | 1.8% |
| Single Population | 60.1% | 52.5% | 50.2% |
| Never Married | 43.6% | 31.4% | 33.8% |
| Divorced | 9.1% | 13.9% | 10.8% |
| Widowed | 7.4% | 7.2% | 5.6% |
| space5 | | | |
| Household Size | 2.56 | 2.49 | 2.60 |
| Households | 795 | 7,158 | 124,010,992 |
| Family Households | 504 | 4,564 | 80,755,759 |
| Married couple, w/children | 30.0% | 33.9% | 30.5% |
| Married couple, no children | 35.3% | 37.6% | 42.9% |
| Non Family Households | 291 | 2,594 | 43,255,233 |
| Single householder, w/children | 14.3% | 19.1% | 15.8% |
| Single householder, no children | 20.4% | 9.4% | 10.8% |