| | Jefferson, NY | Lewes, DE | United States |
| Population | 1,355 | 3,257 | 329,725,481 |
| Female Population | 48.9% | 49.1% | 50.5% |
| Male Population | 51.1% | 50.9% | 49.5% |
| Median Age | 52.1 | 65.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,402 | 2,858 | 309,327,143 |
| Population - 2000 | 1,285 | 2,932 | 285,036,114 |
| Population - 1990 | 1,190 | 2,295 | 251,960,433 |
| Pop. 2000 to Now | 13.2% | 16.5% | 15.6% |
| Pop. 1990 to Now | 22.3% | 48.9% | 30.8% |
| space4 | | | |
| Population Density | 31.3 | 842.7 | 93.4 |
| Land Area | 43.3 | 3.9 | 3,531,905.4 |
| Water Area | 0.2 | 0.9 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Jefferson, NY | Lewes, DE | United States |
| Age 0 to 4 | 3.8% | 0.5% | 5.9% |
| Age 5 to 9 | 1.5% | 1.6% | 6.1% |
| Age 10 to 14 | 4.4% | 3.3% | 6.6% |
| Age 15 to 17 | 4.9% | 0.1% | 3.9% |
| Age 18 to 20 | 1.7% | 0.0% | 4.0% |
| Age 21 to 24 | 3.1% | 2.1% | 5.2% |
| Age 25 to 34 | 6.6% | 8.8% | 13.8% |
| Age 35 to 44 | 8.1% | 6.0% | 12.9% |
| Age 45 to 54 | 23.4% | 3.5% | 12.6% |
| Age 55 to 59 | 6.6% | 7.5% | 6.7% |
| Age 60 to 64 | 10.1% | 13.1% | 6.3% |
| Age 65 to 74 | 15.9% | 32.3% | 9.6% |
| Age 75 to 84 | 6.1% | 16.8% | 4.5% |
| Age 85 and over | 3.9% | 4.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Jefferson, NY | Lewes, DE | United States |
| White | 91.7% | 96.1% | 59.4% |
| Black | 0.0% | 1.0% | 12.2% |
| Asian | 2.2% | 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 | 4.9% | 1.3% | 3.2% |
| Hispanic | 1.1% | 1.5% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Jefferson, NY | Lewes, DE | United States |
| Married Population | 48.7% | 62.2% | 49.8% |
| Currently Married | 47.6% | 61.9% | 48.0% |
| Married but Separated | 1.1% | 0.3% | 1.8% |
| Single Population | 51.3% | 37.8% | 50.2% |
| Never Married | 27.0% | 19.4% | 33.8% |
| Divorced | 13.4% | 8.7% | 10.8% |
| Widowed | 10.9% | 9.6% | 5.6% |
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| Household Size | 2.24 | 2.00 | 2.60 |
| Households | 605 | 1,546 | 124,010,992 |
| Family Households | 363 | 1,040 | 80,755,759 |
| Married couple, w/children | 23.4% | 9.4% | 30.5% |
| Married couple, no children | 56.7% | 81.7% | 42.9% |
| Non Family Households | 242 | 506 | 43,255,233 |
| Single householder, w/children | 16.0% | 0.0% | 15.8% |
| Single householder, no children | 3.9% | 8.8% | 10.8% |