| | Erie, KS | Girard, KS | United States |
| Population | 1,443 | 2,648 | 329,725,481 |
| Female Population | 52.7% | 51.4% | 50.5% |
| Male Population | 47.3% | 48.6% | 49.5% |
| Median Age | 39.1 | 39.2 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,153 | 2,782 | 309,327,143 |
| Population - 2000 | 1,211 | 2,773 | 285,036,114 |
| Population - 1990 | 1,276 | 2,794 | 251,960,433 |
| Pop. 2000 to Now | -10.7% | -4.2% | 15.6% |
| Pop. 1990 to Now | -15.3% | -4.9% | 30.8% |
| space4 | | | |
| Population Density | 1,138.0 | 1,134.1 | 93.4 |
| Land Area | 1.3 | 2.3 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Erie, KS | Girard, KS | United States |
| Age 0 to 4 | 11.6% | 4.6% | 5.9% |
| Age 5 to 9 | 3.5% | 5.9% | 6.1% |
| Age 10 to 14 | 8.5% | 5.0% | 6.6% |
| Age 15 to 17 | 2.8% | 4.6% | 3.9% |
| Age 18 to 20 | 0.7% | 3.0% | 4.0% |
| Age 21 to 24 | 7.4% | 11.3% | 5.2% |
| Age 25 to 34 | 13.7% | 11.1% | 13.8% |
| Age 35 to 44 | 6.3% | 10.2% | 12.9% |
| Age 45 to 54 | 6.1% | 11.0% | 12.6% |
| Age 55 to 59 | 11.4% | 4.2% | 6.7% |
| Age 60 to 64 | 6.7% | 5.3% | 6.3% |
| Age 65 to 74 | 10.7% | 16.6% | 9.6% |
| Age 75 to 84 | 8.5% | 5.4% | 4.5% |
| Age 85 and over | 2.1% | 1.9% | 1.9% |
| space1 | | | |
| Race | | | |
| | Erie, KS | Girard, KS | United States |
| White | 87.9% | 93.8% | 59.4% |
| Black | 4.0% | 0.7% | 12.2% |
| Asian | 0.0% | 0.0% | 5.6% |
| Native American | 1.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 2.4% | 2.7% | 3.2% |
| Hispanic | 4.7% | 2.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Erie, KS | Girard, KS | United States |
| Married Population | 47.8% | 39.9% | 49.8% |
| Currently Married | 46.4% | 37.4% | 48.0% |
| Married but Separated | 1.4% | 2.4% | 1.8% |
| Single Population | 52.2% | 60.1% | 50.2% |
| Never Married | 22.1% | 34.9% | 33.8% |
| Divorced | 16.6% | 17.5% | 10.8% |
| Widowed | 13.5% | 7.7% | 5.6% |
| space5 | | | |
| Household Size | 2.45 | 2.41 | 2.60 |
| Households | 577 | 1,040 | 124,010,992 |
| Family Households | 309 | 609 | 80,755,759 |
| Married couple, w/children | 30.1% | 25.6% | 30.5% |
| Married couple, no children | 44.0% | 30.0% | 42.9% |
| Non Family Households | 268 | 431 | 43,255,233 |
| Single householder, w/children | 16.5% | 31.0% | 15.8% |
| Single householder, no children | 9.4% | 13.3% | 10.8% |