| | Frederick, MD | Peoria, AZ | United States |
| Population | 76,376 | 187,733 | 329,725,481 |
| Female Population | 51.0% | 51.9% | 50.5% |
| Male Population | 49.0% | 48.1% | 49.5% |
| Median Age | 36.9 | 40.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 65,508 | 154,856 | 309,327,143 |
| Population - 2000 | 52,767 | 108,364 | 285,036,114 |
| Population - 1990 | 40,148 | 50,618 | 251,960,433 |
| Pop. 2000 to Now | 38.9% | 66.0% | 15.6% |
| Pop. 1990 to Now | 82.6% | 255.4% | 30.8% |
| space4 | | | |
| Population Density | 3,297.3 | 1,068.5 | 93.4 |
| Land Area | 23.2 | 175.7 | 3,531,905.4 |
| Water Area | 0.2 | 3.4 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Frederick, MD | Peoria, AZ | United States |
| Age 0 to 4 | 5.9% | 5.5% | 5.9% |
| Age 5 to 9 | 5.8% | 6.6% | 6.1% |
| Age 10 to 14 | 6.7% | 6.8% | 6.6% |
| Age 15 to 17 | 3.7% | 4.4% | 3.9% |
| Age 18 to 20 | 3.6% | 3.0% | 4.0% |
| Age 21 to 24 | 5.5% | 4.3% | 5.2% |
| Age 25 to 34 | 15.7% | 11.3% | 13.8% |
| Age 35 to 44 | 14.3% | 13.6% | 12.9% |
| Age 45 to 54 | 13.1% | 12.6% | 12.6% |
| Age 55 to 59 | 6.9% | 7.2% | 6.7% |
| Age 60 to 64 | 5.0% | 7.0% | 6.3% |
| Age 65 to 74 | 8.0% | 10.8% | 9.6% |
| Age 75 to 84 | 3.9% | 4.9% | 4.5% |
| Age 85 and over | 1.8% | 2.2% | 1.9% |
| space1 | | | |
| Race | | | |
| | Frederick, MD | Peoria, AZ | United States |
| White | 54.9% | 66.0% | 59.4% |
| Black | 17.1% | 3.0% | 12.2% |
| Asian | 5.1% | 5.3% | 5.6% |
| Native American | 0.2% | 0.6% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.2% | 0.2% |
| Other | 0.2% | 0.2% | 0.4% |
| Two or More Races | 4.9% | 4.1% | 3.2% |
| Hispanic | 17.5% | 20.6% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Frederick, MD | Peoria, AZ | United States |
| Married Population | 47.9% | 56.3% | 49.8% |
| Currently Married | 45.7% | 55.0% | 48.0% |
| Married but Separated | 2.2% | 1.4% | 1.8% |
| Single Population | 52.1% | 43.7% | 50.2% |
| Never Married | 35.0% | 26.1% | 33.8% |
| Divorced | 11.7% | 11.8% | 10.8% |
| Widowed | 5.4% | 5.8% | 5.6% |
| space5 | | | |
| Household Size | 2.43 | 2.65 | 2.60 |
| Households | 30,644 | 70,471 | 124,010,992 |
| Family Households | 18,686 | 50,307 | 80,755,759 |
| Married couple, w/children | 34.7% | 31.5% | 30.5% |
| Married couple, no children | 35.7% | 45.5% | 42.9% |
| Non Family Households | 11,958 | 20,164 | 43,255,233 |
| Single householder, w/children | 18.2% | 13.7% | 15.8% |
| Single householder, no children | 11.4% | 9.3% | 10.8% |