| | Foss, OK | Harker Heights, TX | United States |
| Population | 121 | 32,320 | 329,725,481 |
| Female Population | 43.0% | 50.2% | 50.5% |
| Male Population | 57.0% | 49.9% | 49.5% |
| Median Age | 56.6 | 33.8 | 38.4 |
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| Population - 2010 | 151 | 26,978 | 309,327,143 |
| Population - 2000 | 127 | 17,308 | 285,036,114 |
| Population - 1990 | 148 | 12,841 | 251,960,433 |
| Pop. 2000 to Now | 15.0% | 91.1% | 15.6% |
| Pop. 1990 to Now | -1.4% | 157.5% | 30.8% |
| space4 | | | |
| Population Density | 166.4 | 2,065.8 | 93.4 |
| Land Area | 0.7 | 15.6 | 3,531,905.4 |
| Water Area | 0.0 | 0.1 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Foss, OK | Harker Heights, TX | United States |
| Age 0 to 4 | 0.0% | 6.1% | 5.9% |
| Age 5 to 9 | 8.3% | 8.5% | 6.1% |
| Age 10 to 14 | 0.8% | 8.6% | 6.6% |
| Age 15 to 17 | 4.1% | 5.3% | 3.9% |
| Age 18 to 20 | 6.6% | 4.8% | 4.0% |
| Age 21 to 24 | 0.0% | 3.5% | 5.2% |
| Age 25 to 34 | 7.4% | 14.1% | 13.8% |
| Age 35 to 44 | 13.2% | 17.6% | 12.9% |
| Age 45 to 54 | 7.4% | 11.2% | 12.6% |
| Age 55 to 59 | 4.1% | 6.8% | 6.7% |
| Age 60 to 64 | 9.1% | 3.8% | 6.3% |
| Age 65 to 74 | 12.4% | 7.1% | 9.6% |
| Age 75 to 84 | 24.0% | 1.8% | 4.5% |
| Age 85 and over | 2.5% | 0.9% | 1.9% |
| space1 | | | |
| Race | | | |
| | Foss, OK | Harker Heights, TX | United States |
| White | 73.6% | 44.2% | 59.4% |
| Black | 0.0% | 25.8% | 12.2% |
| Asian | 0.8% | 3.6% | 5.6% |
| Native American | 4.1% | 0.3% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.5% | 0.2% |
| Other | 0.0% | 0.1% | 0.4% |
| Two or More Races | 15.7% | 6.0% | 3.2% |
| Hispanic | 5.8% | 19.5% | 18.4% |
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| Marriage & Family | | | |
| | Foss, OK | Harker Heights, TX | United States |
| Married Population | 63.6% | 50.2% | 49.8% |
| Currently Married | 63.6% | 48.1% | 48.0% |
| Married but Separated | 0.0% | 2.1% | 1.8% |
| Single Population | 36.4% | 49.8% | 50.2% |
| Never Married | 20.0% | 32.9% | 33.8% |
| Divorced | 9.1% | 13.1% | 10.8% |
| Widowed | 7.3% | 3.8% | 5.6% |
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| Household Size | 2.42 | 2.81 | 2.60 |
| Households | 50 | 11,426 | 124,010,992 |
| Family Households | 28 | 8,211 | 80,755,759 |
| Married couple, w/children | 25.0% | 34.0% | 30.5% |
| Married couple, no children | 60.7% | 31.7% | 42.9% |
| Non Family Households | 22 | 3,215 | 43,255,233 |
| Single householder, w/children | 3.6% | 26.0% | 15.8% |
| Single householder, no children | 10.7% | 8.3% | 10.8% |