| | Union Gap, WA | Tacoma, WA | United States |
| Population | 6,499 | 217,332 | 329,725,481 |
| Female Population | 49.9% | 49.6% | 50.5% |
| Male Population | 50.1% | 50.4% | 49.5% |
| Median Age | 33.4 | 36.7 | 38.4 |
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| Population - 2010 | 6,132 | 198,324 | 309,327,143 |
| Population - 2000 | 5,621 | 193,556 | 285,036,114 |
| Population - 1990 | 3,120 | 176,664 | 251,960,433 |
| Pop. 2000 to Now | 9.6% | 13.6% | 15.6% |
| Pop. 1990 to Now | 97.4% | 24.5% | 30.8% |
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| Population Density | 1,164.3 | 4,371.8 | 93.4 |
| Land Area | 5.6 | 49.7 | 3,531,905.4 |
| Water Area | 0.0 | 12.7 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Union Gap, WA | Tacoma, WA | United States |
| Age 0 to 4 | 8.5% | 6.2% | 5.9% |
| Age 5 to 9 | 8.6% | 5.6% | 6.1% |
| Age 10 to 14 | 4.9% | 5.8% | 6.6% |
| Age 15 to 17 | 5.3% | 3.1% | 3.9% |
| Age 18 to 20 | 6.2% | 3.2% | 4.0% |
| Age 21 to 24 | 4.2% | 5.8% | 5.2% |
| Age 25 to 34 | 13.8% | 17.3% | 13.8% |
| Age 35 to 44 | 15.0% | 14.9% | 12.9% |
| Age 45 to 54 | 11.2% | 12.3% | 12.6% |
| Age 55 to 59 | 9.1% | 6.1% | 6.7% |
| Age 60 to 64 | 2.9% | 5.9% | 6.3% |
| Age 65 to 74 | 5.5% | 8.7% | 9.6% |
| Age 75 to 84 | 3.4% | 3.6% | 4.5% |
| Age 85 and over | 1.4% | 1.5% | 1.9% |
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| Race | | | |
| | Union Gap, WA | Tacoma, WA | United States |
| White | 38.2% | 57.0% | 59.4% |
| Black | 0.0% | 10.3% | 12.2% |
| Asian | 3.2% | 8.6% | 5.6% |
| Native American | 6.3% | 1.3% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.9% | 0.2% |
| Other | 0.0% | 0.6% | 0.4% |
| Two or More Races | 0.9% | 9.1% | 3.2% |
| Hispanic | 51.4% | 12.2% | 18.4% |
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| Marriage & Family | | | |
| | Union Gap, WA | Tacoma, WA | United States |
| Married Population | 46.5% | 44.8% | 49.8% |
| Currently Married | 41.9% | 43.1% | 48.0% |
| Married but Separated | 4.6% | 1.7% | 1.8% |
| Single Population | 53.5% | 55.3% | 50.2% |
| Never Married | 41.4% | 36.8% | 33.8% |
| Divorced | 7.6% | 13.6% | 10.8% |
| Widowed | 4.5% | 4.8% | 5.6% |
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| Household Size | 3.10 | 2.42 | 2.60 |
| Households | 2,073 | 87,379 | 124,010,992 |
| Family Households | 1,464 | 50,920 | 80,755,759 |
| Married couple, w/children | 26.7% | 27.7% | 30.5% |
| Married couple, no children | 38.8% | 40.9% | 42.9% |
| Non Family Households | 609 | 36,459 | 43,255,233 |
| Single householder, w/children | 25.7% | 18.9% | 15.8% |
| Single householder, no children | 8.8% | 12.4% | 10.8% |