| | Castalia, NC | Erwin, NC | United States |
| Population | 299 | 4,600 | 329,725,481 |
| Female Population | 49.8% | 52.1% | 50.5% |
| Male Population | 50.2% | 47.9% | 49.5% |
| Median Age | 46.8 | 42.2 | 38.4 |
| space3 | | | |
| Population - 2010 | 265 | 4,565 | 309,327,143 |
| Population - 2000 | 340 | 4,537 | 285,036,114 |
| Population - 1990 | 261 | 4,061 | 251,960,433 |
| Pop. 2000 to Now | -19.7% | 14.7% | 15.6% |
| Pop. 1990 to Now | 4.6% | 28.1% | 30.8% |
| space4 | | | |
| Population Density | 397.1 | 1,091.1 | 93.4 |
| Land Area | 0.8 | 4.2 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Castalia, NC | Erwin, NC | United States |
| Age 0 to 4 | 3.7% | 9.0% | 5.9% |
| Age 5 to 9 | 7.7% | 5.1% | 6.1% |
| Age 10 to 14 | 3.3% | 5.7% | 6.6% |
| Age 15 to 17 | 1.0% | 3.4% | 3.9% |
| Age 18 to 20 | 1.7% | 3.2% | 4.0% |
| Age 21 to 24 | 7.4% | 3.3% | 5.2% |
| Age 25 to 34 | 12.0% | 13.9% | 13.8% |
| Age 35 to 44 | 6.0% | 9.2% | 12.9% |
| Age 45 to 54 | 16.7% | 12.6% | 12.6% |
| Age 55 to 59 | 5.4% | 7.2% | 6.7% |
| Age 60 to 64 | 5.4% | 6.7% | 6.3% |
| Age 65 to 74 | 18.7% | 10.0% | 9.6% |
| Age 75 to 84 | 9.4% | 8.5% | 4.5% |
| Age 85 and over | 1.7% | 2.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Castalia, NC | Erwin, NC | United States |
| White | 36.8% | 64.0% | 59.4% |
| Black | 62.5% | 20.1% | 12.2% |
| Asian | 0.0% | 0.1% | 5.6% |
| Native American | 0.0% | 0.5% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.3% | 0.4% |
| Two or More Races | 0.7% | 1.8% | 3.2% |
| Hispanic | 0.0% | 13.3% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Castalia, NC | Erwin, NC | United States |
| Married Population | 43.9% | 48.6% | 49.8% |
| Currently Married | 37.3% | 45.7% | 48.0% |
| Married but Separated | 6.7% | 2.8% | 1.8% |
| Single Population | 56.1% | 51.4% | 50.2% |
| Never Married | 32.2% | 29.4% | 33.8% |
| Divorced | 12.9% | 12.5% | 10.8% |
| Widowed | 11.0% | 9.6% | 5.6% |
| space5 | | | |
| Household Size | 2.39 | 2.70 | 2.60 |
| Households | 125 | 1,664 | 124,010,992 |
| Family Households | 102 | 1,114 | 80,755,759 |
| Married couple, w/children | 3.9% | 27.2% | 30.5% |
| Married couple, no children | 42.2% | 47.2% | 42.9% |
| Non Family Households | 23 | 550 | 43,255,233 |
| Single householder, w/children | 20.6% | 17.0% | 15.8% |
| Single householder, no children | 33.3% | 8.6% | 10.8% |