| | Birch Bay, WA | Custer, WA | United States |
| Population | 10,062 | 412 | 329,725,481 |
| Female Population | 46.7% | 44.9% | 50.5% |
| Male Population | 53.3% | 55.1% | 49.5% |
| Median Age | 46.9 | 42.3 | 38.4 |
| space3 | | | |
| Population - 2010 | 7,881 | 532 | 309,327,143 |
| Population - 2000 | 4,961 | 299 | 285,036,114 |
| Population - 1990 | 2,656 | 282 | 251,960,433 |
| Pop. 2000 to Now | 89.9% | -45.8% | 15.6% |
| Pop. 1990 to Now | 254.7% | -42.6% | 30.8% |
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| Population Density | 628.1 | 226.0 | 93.4 |
| Land Area | 16.0 | 1.8 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Birch Bay, WA | Custer, WA | United States |
| Age 0 to 4 | 6.4% | 4.9% | 5.9% |
| Age 5 to 9 | 4.9% | 4.6% | 6.1% |
| Age 10 to 14 | 4.9% | 9.7% | 6.6% |
| Age 15 to 17 | 2.5% | 0.0% | 3.9% |
| Age 18 to 20 | 1.4% | 10.4% | 4.0% |
| Age 21 to 24 | 5.4% | 0.0% | 5.2% |
| Age 25 to 34 | 10.9% | 10.4% | 13.8% |
| Age 35 to 44 | 10.1% | 23.5% | 12.9% |
| Age 45 to 54 | 13.1% | 1.0% | 12.6% |
| Age 55 to 59 | 8.7% | 15.3% | 6.7% |
| Age 60 to 64 | 8.2% | 0.0% | 6.3% |
| Age 65 to 74 | 15.0% | 14.1% | 9.6% |
| Age 75 to 84 | 6.8% | 6.1% | 4.5% |
| Age 85 and over | 1.7% | 0.0% | 1.9% |
| space1 | | | |
| Race | | | |
| | Birch Bay, WA | Custer, WA | United States |
| White | 79.4% | 94.4% | 59.4% |
| Black | 0.0% | 0.0% | 12.2% |
| Asian | 1.7% | 0.0% | 5.6% |
| Native American | 1.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.7% | 0.0% | 0.2% |
| Other | 0.2% | 0.0% | 0.4% |
| Two or More Races | 10.1% | 0.0% | 3.2% |
| Hispanic | 6.9% | 5.6% | 18.4% |
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| Marriage & Family | | | |
| | Birch Bay, WA | Custer, WA | United States |
| Married Population | 61.0% | 56.8% | 49.8% |
| Currently Married | 57.0% | 55.6% | 48.0% |
| Married but Separated | 4.0% | 1.2% | 1.8% |
| Single Population | 39.0% | 43.2% | 50.2% |
| Never Married | 22.7% | 43.2% | 33.8% |
| Divorced | 11.7% | 0.0% | 10.8% |
| Widowed | 4.5% | 0.0% | 5.6% |
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| Household Size | 2.20 | 2.62 | 2.60 |
| Households | 4,570 | 157 | 124,010,992 |
| Family Households | 2,916 | 108 | 80,755,759 |
| Married couple, w/children | 21.4% | 17.6% | 30.5% |
| Married couple, no children | 58.1% | 69.4% | 42.9% |
| Non Family Households | 1,654 | 49 | 43,255,233 |
| Single householder, w/children | 14.6% | 13.0% | 15.8% |
| Single householder, no children | 5.9% | 0.0% | 10.8% |