| | Grundy Center, IA | Thomaston, AL | United States |
| Population | 2,783 | 469 | 329,725,481 |
| Female Population | 54.4% | 47.3% | 50.5% |
| Male Population | 45.6% | 52.7% | 49.5% |
| Median Age | 39.5 | 47.6 | 38.4 |
| space3 | | | |
| Population - 2010 | 2,706 | 424 | 309,327,143 |
| Population - 2000 | 2,596 | 383 | 285,036,114 |
| Population - 1990 | 2,491 | 497 | 251,960,433 |
| Pop. 2000 to Now | 2.9% | 0.0% | 15.6% |
| Pop. 1990 to Now | 7.2% | -22.9% | 30.8% |
| space4 | | | |
| Population Density | 1,077.0 | 233.0 | 93.4 |
| Land Area | 2.6 | 2.0 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Grundy Center, IA | Thomaston, AL | United States |
| Age 0 to 4 | 4.3% | 7.7% | 5.9% |
| Age 5 to 9 | 8.3% | 7.5% | 6.1% |
| Age 10 to 14 | 10.2% | 3.8% | 6.6% |
| Age 15 to 17 | 5.4% | 0.0% | 3.9% |
| Age 18 to 20 | 2.3% | 0.4% | 4.0% |
| Age 21 to 24 | 2.8% | 5.5% | 5.2% |
| Age 25 to 34 | 9.1% | 6.0% | 13.8% |
| Age 35 to 44 | 16.3% | 16.6% | 12.9% |
| Age 45 to 54 | 9.2% | 23.5% | 12.6% |
| Age 55 to 59 | 6.3% | 6.8% | 6.7% |
| Age 60 to 64 | 5.0% | 7.7% | 6.3% |
| Age 65 to 74 | 9.7% | 10.2% | 9.6% |
| Age 75 to 84 | 8.0% | 2.3% | 4.5% |
| Age 85 and over | 3.4% | 1.9% | 1.9% |
| space1 | | | |
| Race | | | |
| | Grundy Center, IA | Thomaston, AL | United States |
| White | 96.8% | 50.5% | 59.4% |
| Black | 0.0% | 49.5% | 12.2% |
| Asian | 0.8% | 0.0% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 1.4% | 0.0% | 0.4% |
| Two or More Races | 0.3% | 0.0% | 3.2% |
| Hispanic | 0.7% | 0.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Grundy Center, IA | Thomaston, AL | United States |
| Married Population | 56.4% | 54.5% | 49.8% |
| Currently Married | 54.9% | 41.3% | 48.0% |
| Married but Separated | 1.5% | 13.2% | 1.8% |
| Single Population | 43.6% | 45.5% | 50.2% |
| Never Married | 27.0% | 24.5% | 33.8% |
| Divorced | 10.1% | 13.7% | 10.8% |
| Widowed | 6.4% | 7.4% | 5.6% |
| space5 | | | |
| Household Size | 2.54 | 2.54 | 2.60 |
| Households | 1,070 | 185 | 124,010,992 |
| Family Households | 719 | 115 | 80,755,759 |
| Married couple, w/children | 38.5% | 15.7% | 30.5% |
| Married couple, no children | 38.9% | 54.8% | 42.9% |
| Non Family Households | 351 | 70 | 43,255,233 |
| Single householder, w/children | 15.9% | 14.8% | 15.8% |
| Single householder, no children | 6.7% | 14.8% | 10.8% |