| | Grimes, IA | Creston, IA | United States |
| Population | 14,842 | 7,594 | 329,725,481 |
| Female Population | 47.9% | 51.4% | 50.5% |
| Male Population | 52.1% | 48.6% | 49.5% |
| Median Age | 35.6 | 38.2 | 38.4 |
| space3 | | | |
| Population - 2010 | 8,412 | 7,824 | 309,327,143 |
| Population - 2000 | 5,098 | 7,597 | 285,036,114 |
| Population - 1990 | 2,653 | 7,911 | 251,960,433 |
| Pop. 2000 to Now | 210.5% | 0.8% | 15.6% |
| Pop. 1990 to Now | 496.7% | -3.2% | 30.8% |
| space4 | | | |
| Population Density | 1,267.7 | 1,463.8 | 93.4 |
| Land Area | 11.7 | 5.2 | 3,531,905.4 |
| Water Area | 0.0 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Grimes, IA | Creston, IA | United States |
| Age 0 to 4 | 8.5% | 6.1% | 5.9% |
| Age 5 to 9 | 6.9% | 4.8% | 6.1% |
| Age 10 to 14 | 8.2% | 6.4% | 6.6% |
| Age 15 to 17 | 5.7% | 4.4% | 3.9% |
| Age 18 to 20 | 3.4% | 6.4% | 4.0% |
| Age 21 to 24 | 3.0% | 6.1% | 5.2% |
| Age 25 to 34 | 12.7% | 11.9% | 13.8% |
| Age 35 to 44 | 21.5% | 12.4% | 12.9% |
| Age 45 to 54 | 13.7% | 11.3% | 12.6% |
| Age 55 to 59 | 5.6% | 5.2% | 6.7% |
| Age 60 to 64 | 3.5% | 6.6% | 6.3% |
| Age 65 to 74 | 5.6% | 9.9% | 9.6% |
| Age 75 to 84 | 1.3% | 5.8% | 4.5% |
| Age 85 and over | 0.5% | 2.5% | 1.9% |
| space1 | | | |
| Race | | | |
| | Grimes, IA | Creston, IA | United States |
| White | 91.4% | 93.3% | 59.4% |
| Black | 1.4% | 0.5% | 12.2% |
| Asian | 2.0% | 1.1% | 5.6% |
| Native American | 0.1% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.1% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 0.9% | 2.5% | 3.2% |
| Hispanic | 4.2% | 2.6% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Grimes, IA | Creston, IA | United States |
| Married Population | 54.9% | 44.7% | 49.8% |
| Currently Married | 54.4% | 43.2% | 48.0% |
| Married but Separated | 0.5% | 1.5% | 1.8% |
| Single Population | 45.1% | 55.3% | 50.2% |
| Never Married | 27.2% | 31.8% | 33.8% |
| Divorced | 15.1% | 16.9% | 10.8% |
| Widowed | 2.8% | 6.6% | 5.6% |
| space5 | | | |
| Household Size | 2.59 | 2.31 | 2.60 |
| Households | 5,736 | 3,181 | 124,010,992 |
| Family Households | 3,395 | 1,753 | 80,755,759 |
| Married couple, w/children | 53.5% | 29.9% | 30.5% |
| Married couple, no children | 30.4% | 44.9% | 42.9% |
| Non Family Households | 2,341 | 1,428 | 43,255,233 |
| Single householder, w/children | 13.3% | 17.6% | 15.8% |
| Single householder, no children | 2.7% | 7.5% | 10.8% |