| | Springfield, OR | Grinnell, IA | United States |
| Population | 62,138 | 9,481 | 329,725,481 |
| Female Population | 49.4% | 53.9% | 50.5% |
| Male Population | 50.7% | 46.1% | 49.5% |
| Median Age | 37.3 | 38.6 | 38.4 |
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| Population - 2010 | 59,444 | 9,221 | 309,327,143 |
| Population - 2000 | 52,864 | 9,105 | 285,036,114 |
| Population - 1990 | 44,683 | 8,902 | 251,960,433 |
| Pop. 2000 to Now | 19.6% | -0.1% | 15.6% |
| Pop. 1990 to Now | 41.5% | 2.2% | 30.8% |
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| Population Density | 3,925.3 | 1,676.0 | 93.4 |
| Land Area | 15.8 | 5.7 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Springfield, OR | Grinnell, IA | United States |
| Age 0 to 4 | 6.0% | 3.2% | 5.9% |
| Age 5 to 9 | 5.8% | 4.6% | 6.1% |
| Age 10 to 14 | 6.1% | 7.2% | 6.6% |
| Age 15 to 17 | 3.7% | 3.9% | 3.9% |
| Age 18 to 20 | 4.1% | 15.0% | 4.0% |
| Age 21 to 24 | 6.0% | 6.7% | 5.2% |
| Age 25 to 34 | 14.4% | 7.2% | 13.8% |
| Age 35 to 44 | 13.4% | 10.5% | 12.9% |
| Age 45 to 54 | 12.8% | 10.0% | 12.6% |
| Age 55 to 59 | 7.0% | 3.8% | 6.7% |
| Age 60 to 64 | 5.9% | 6.6% | 6.3% |
| Age 65 to 74 | 9.0% | 9.4% | 9.6% |
| Age 75 to 84 | 3.9% | 7.9% | 4.5% |
| Age 85 and over | 1.9% | 4.0% | 1.9% |
| space1 | | | |
| Race | | | |
| | Springfield, OR | Grinnell, IA | United States |
| White | 78.0% | 88.4% | 59.4% |
| Black | 0.8% | 2.3% | 12.2% |
| Asian | 1.6% | 4.1% | 5.6% |
| Native American | 1.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.1% | 0.0% | 0.2% |
| Other | 0.1% | 0.0% | 0.4% |
| Two or More Races | 5.7% | 2.2% | 3.2% |
| Hispanic | 12.6% | 3.0% | 18.4% |
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| Marriage & Family | | | |
| | Springfield, OR | Grinnell, IA | United States |
| Married Population | 46.5% | 36.7% | 49.8% |
| Currently Married | 43.7% | 36.3% | 48.0% |
| Married but Separated | 2.8% | 0.5% | 1.8% |
| Single Population | 53.5% | 63.3% | 50.2% |
| Never Married | 33.6% | 40.8% | 33.8% |
| Divorced | 15.2% | 12.8% | 10.8% |
| Widowed | 4.7% | 9.7% | 5.6% |
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| Household Size | 2.45 | 2.13 | 2.60 |
| Households | 25,140 | 3,766 | 124,010,992 |
| Family Households | 15,941 | 1,825 | 80,755,759 |
| Married couple, w/children | 26.7% | 29.9% | 30.5% |
| Married couple, no children | 39.7% | 46.5% | 42.9% |
| Non Family Households | 9,199 | 1,941 | 43,255,233 |
| Single householder, w/children | 22.5% | 17.4% | 15.8% |
| Single householder, no children | 11.2% | 6.2% | 10.8% |