| | Spencer, ID | New Meadows, ID | United States |
| Population | 24 | 395 | 329,725,481 |
| Female Population | 37.5% | 40.5% | 50.5% |
| Male Population | 62.5% | 59.5% | 49.5% |
| Median Age | 67.5 | 33.3 | 38.4 |
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| Population - 2010 | 37 | 490 | 309,327,143 |
| Population - 2000 | 38 | 533 | 285,036,114 |
| Population - 1990 | 11 | 534 | 251,960,433 |
| Pop. 2000 to Now | -13.2% | 3.8% | 15.6% |
| Pop. 1990 to Now | 200.0% | 3.6% | 30.8% |
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| Population Density | 21.0 | 676.4 | 93.4 |
| Land Area | 1.1 | 0.6 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Spencer, ID | New Meadows, ID | United States |
| Age 0 to 4 | 0.0% | 14.2% | 5.9% |
| Age 5 to 9 | 0.0% | 6.1% | 6.1% |
| Age 10 to 14 | 0.0% | 4.3% | 6.6% |
| Age 15 to 17 | 0.0% | 1.3% | 3.9% |
| Age 18 to 20 | 0.0% | 5.6% | 4.0% |
| Age 21 to 24 | 4.2% | 6.6% | 5.2% |
| Age 25 to 34 | 0.0% | 14.2% | 13.8% |
| Age 35 to 44 | 8.3% | 12.2% | 12.9% |
| Age 45 to 54 | 0.0% | 20.0% | 12.6% |
| Age 55 to 59 | 16.7% | 3.8% | 6.7% |
| Age 60 to 64 | 0.0% | 4.8% | 6.3% |
| Age 65 to 74 | 45.8% | 5.8% | 9.6% |
| Age 75 to 84 | 25.0% | 1.3% | 4.5% |
| Age 85 and over | 0.0% | 0.0% | 1.9% |
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| Race | | | |
| | Spencer, ID | New Meadows, ID | United States |
| White | 50.0% | 100.0% | 59.4% |
| Black | 0.0% | 0.0% | 12.2% |
| Asian | 0.0% | 0.0% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 4.2% | 0.0% | 3.2% |
| Hispanic | 45.8% | 0.0% | 18.4% |
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| Marriage & Family | | | |
| | Spencer, ID | New Meadows, ID | United States |
| Married Population | 20.8% | 51.7% | 49.8% |
| Currently Married | 20.8% | 51.7% | 48.0% |
| Married but Separated | 0.0% | 0.0% | 1.8% |
| Single Population | 79.2% | 48.3% | 50.2% |
| Never Married | 12.5% | 24.5% | 33.8% |
| Divorced | 50.0% | 6.0% | 10.8% |
| Widowed | 16.7% | 17.8% | 5.6% |
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| Household Size | 1.26 | 3.36 | 2.60 |
| Households | 19 | 117 | 124,010,992 |
| Family Households | 2 | 88 | 80,755,759 |
| Married couple, w/children | 0.0% | 26.1% | 30.5% |
| Married couple, no children | 100.0% | 51.1% | 42.9% |
| Non Family Households | 17 | 29 | 43,255,233 |
| Single householder, w/children | 0.0% | 14.8% | 15.8% |
| Single householder, no children | 0.0% | 8.0% | 10.8% |