| | Cosmopolis, WA | Brighton, CO | United States |
| Population | 2,097 | 39,895 | 329,725,481 |
| Female Population | 48.6% | 48.5% | 50.5% |
| Male Population | 51.4% | 51.5% | 49.5% |
| Median Age | 39.8 | 34.5 | 38.4 |
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| Population - 2010 | 1,642 | 33,975 | 309,327,143 |
| Population - 2000 | 1,595 | 20,905 | 285,036,114 |
| Population - 1990 | 1,372 | 14,203 | 251,960,433 |
| Pop. 2000 to Now | 5.3% | 95.1% | 15.6% |
| Pop. 1990 to Now | 22.5% | 187.1% | 30.8% |
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| Population Density | 1,515.2 | 1,886.1 | 93.4 |
| Land Area | 1.4 | 21.2 | 3,531,905.4 |
| Water Area | 0.2 | 0.3 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Cosmopolis, WA | Brighton, CO | United States |
| Age 0 to 4 | 4.5% | 6.4% | 5.9% |
| Age 5 to 9 | 13.6% | 8.0% | 6.1% |
| Age 10 to 14 | 3.5% | 9.4% | 6.6% |
| Age 15 to 17 | 6.6% | 4.0% | 3.9% |
| Age 18 to 20 | 1.1% | 3.1% | 4.0% |
| Age 21 to 24 | 3.9% | 3.9% | 5.2% |
| Age 25 to 34 | 12.0% | 15.9% | 13.8% |
| Age 35 to 44 | 12.6% | 14.9% | 12.9% |
| Age 45 to 54 | 16.6% | 13.4% | 12.6% |
| Age 55 to 59 | 4.0% | 6.3% | 6.7% |
| Age 60 to 64 | 6.4% | 4.5% | 6.3% |
| Age 65 to 74 | 9.3% | 6.3% | 9.6% |
| Age 75 to 84 | 5.2% | 3.1% | 4.5% |
| Age 85 and over | 0.7% | 0.7% | 1.9% |
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| Race | | | |
| | Cosmopolis, WA | Brighton, CO | United States |
| White | 81.0% | 55.3% | 59.4% |
| Black | 0.0% | 2.4% | 12.2% |
| Asian | 5.2% | 2.7% | 5.6% |
| Native American | 1.0% | 0.3% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.1% | 0.2% |
| Other | 0.0% | 0.1% | 0.4% |
| Two or More Races | 4.5% | 3.2% | 3.2% |
| Hispanic | 8.3% | 36.0% | 18.4% |
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| Marriage & Family | | | |
| | Cosmopolis, WA | Brighton, CO | United States |
| Married Population | 54.9% | 54.2% | 49.8% |
| Currently Married | 54.4% | 52.7% | 48.0% |
| Married but Separated | 0.5% | 1.5% | 1.8% |
| Single Population | 45.1% | 45.8% | 50.2% |
| Never Married | 30.3% | 29.1% | 33.8% |
| Divorced | 8.1% | 11.7% | 10.8% |
| Widowed | 6.7% | 5.0% | 5.6% |
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| Household Size | 2.85 | 2.96 | 2.60 |
| Households | 736 | 12,973 | 124,010,992 |
| Family Households | 535 | 9,321 | 80,755,759 |
| Married couple, w/children | 33.1% | 40.9% | 30.5% |
| Married couple, no children | 44.5% | 37.9% | 42.9% |
| Non Family Households | 201 | 3,652 | 43,255,233 |
| Single householder, w/children | 14.0% | 14.4% | 15.8% |
| Single householder, no children | 8.4% | 6.8% | 10.8% |