| | Greencastle, PA | Palatka, FL | United States |
| Population | 4,199 | 10,399 | 329,725,481 |
| Female Population | 50.3% | 51.6% | 50.5% |
| Male Population | 49.7% | 48.4% | 49.5% |
| Median Age | 41.3 | 37.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 3,987 | 10,583 | 309,327,143 |
| Population - 2000 | 3,722 | 10,033 | 285,036,114 |
| Population - 1990 | 3,600 | 10,201 | 251,960,433 |
| Pop. 2000 to Now | 7.2% | 4.2% | 15.6% |
| Pop. 1990 to Now | 10.8% | 2.5% | 30.8% |
| space4 | | | |
| Population Density | 2,644.2 | 1,077.7 | 93.4 |
| Land Area | 1.6 | 9.6 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Greencastle, PA | Palatka, FL | United States |
| Age 0 to 4 | 10.8% | 8.4% | 5.9% |
| Age 5 to 9 | 7.8% | 5.5% | 6.1% |
| Age 10 to 14 | 5.0% | 8.9% | 6.6% |
| Age 15 to 17 | 3.0% | 2.2% | 3.9% |
| Age 18 to 20 | 3.0% | 2.0% | 4.0% |
| Age 21 to 24 | 2.9% | 6.0% | 5.2% |
| Age 25 to 34 | 12.3% | 14.4% | 13.8% |
| Age 35 to 44 | 12.0% | 7.5% | 12.9% |
| Age 45 to 54 | 9.9% | 10.1% | 12.6% |
| Age 55 to 59 | 6.7% | 7.9% | 6.7% |
| Age 60 to 64 | 8.9% | 5.1% | 6.3% |
| Age 65 to 74 | 7.6% | 11.2% | 9.6% |
| Age 75 to 84 | 8.3% | 8.1% | 4.5% |
| Age 85 and over | 1.9% | 2.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Greencastle, PA | Palatka, FL | United States |
| White | 90.0% | 50.1% | 59.4% |
| Black | 1.8% | 39.7% | 12.2% |
| Asian | 1.4% | 1.4% | 5.6% |
| Native American | 0.0% | 0.8% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.2% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 5.9% | 2.9% | 3.2% |
| Hispanic | 1.0% | 5.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Greencastle, PA | Palatka, FL | United States |
| Married Population | 58.8% | 27.2% | 49.8% |
| Currently Married | 58.2% | 22.6% | 48.0% |
| Married but Separated | 0.6% | 4.6% | 1.8% |
| Single Population | 41.2% | 72.8% | 50.2% |
| Never Married | 23.8% | 45.9% | 33.8% |
| Divorced | 9.8% | 14.6% | 10.8% |
| Widowed | 7.7% | 12.2% | 5.6% |
| space5 | | | |
| Household Size | 2.58 | 2.32 | 2.60 |
| Households | 1,623 | 4,267 | 124,010,992 |
| Family Households | 1,105 | 2,108 | 80,755,759 |
| Married couple, w/children | 27.9% | 12.6% | 30.5% |
| Married couple, no children | 47.8% | 23.2% | 42.9% |
| Non Family Households | 518 | 2,159 | 43,255,233 |
| Single householder, w/children | 14.0% | 38.7% | 15.8% |
| Single householder, no children | 10.3% | 25.6% | 10.8% |