| | Marshalltown, IA | Gig Harbor, WA | United States |
| Population | 27,570 | 11,505 | 329,725,481 |
| Female Population | 49.6% | 53.9% | 50.5% |
| Male Population | 50.4% | 46.1% | 49.5% |
| Median Age | 36 | 41.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 27,605 | 7,124 | 309,327,143 |
| Population - 2000 | 26,009 | 6,465 | 285,036,114 |
| Population - 1990 | 25,178 | 3,236 | 251,960,433 |
| Pop. 2000 to Now | 2.8% | 68.2% | 15.6% |
| Pop. 1990 to Now | 6.2% | 236.0% | 30.8% |
| space4 | | | |
| Population Density | 1,429.9 | 1,949.7 | 93.4 |
| Land Area | 19.3 | 5.9 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Marshalltown, IA | Gig Harbor, WA | United States |
| Age 0 to 4 | 7.1% | 7.1% | 5.9% |
| Age 5 to 9 | 7.1% | 6.6% | 6.1% |
| Age 10 to 14 | 8.2% | 7.5% | 6.6% |
| Age 15 to 17 | 4.1% | 3.1% | 3.9% |
| Age 18 to 20 | 3.7% | 4.0% | 4.0% |
| Age 21 to 24 | 6.1% | 3.7% | 5.2% |
| Age 25 to 34 | 12.0% | 10.0% | 13.8% |
| Age 35 to 44 | 11.9% | 10.9% | 12.9% |
| Age 45 to 54 | 11.0% | 9.9% | 12.6% |
| Age 55 to 59 | 6.2% | 6.0% | 6.7% |
| Age 60 to 64 | 5.3% | 5.9% | 6.3% |
| Age 65 to 74 | 9.7% | 12.4% | 9.6% |
| Age 75 to 84 | 4.8% | 8.3% | 4.5% |
| Age 85 and over | 2.9% | 4.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Marshalltown, IA | Gig Harbor, WA | United States |
| White | 57.9% | 80.4% | 59.4% |
| Black | 1.4% | 0.4% | 12.2% |
| Asian | 4.7% | 4.5% | 5.6% |
| Native American | 0.3% | 0.7% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.3% | 0.2% |
| Other | 0.2% | 0.5% | 0.4% |
| Two or More Races | 3.3% | 6.1% | 3.2% |
| Hispanic | 32.3% | 7.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Marshalltown, IA | Gig Harbor, WA | United States |
| Married Population | 52.1% | 62.2% | 49.8% |
| Currently Married | 50.8% | 61.1% | 48.0% |
| Married but Separated | 1.2% | 1.1% | 1.8% |
| Single Population | 47.9% | 37.8% | 50.2% |
| Never Married | 31.4% | 19.2% | 33.8% |
| Divorced | 10.6% | 10.1% | 10.8% |
| Widowed | 5.9% | 8.5% | 5.6% |
| space5 | | | |
| Household Size | 2.62 | 2.42 | 2.60 |
| Households | 10,098 | 4,672 | 124,010,992 |
| Family Households | 6,522 | 2,986 | 80,755,759 |
| Married couple, w/children | 37.3% | 38.1% | 30.5% |
| Married couple, no children | 39.7% | 50.3% | 42.9% |
| Non Family Households | 3,576 | 1,686 | 43,255,233 |
| Single householder, w/children | 18.6% | 7.7% | 15.8% |
| Single householder, no children | 4.4% | 3.8% | 10.8% |