| | Okemos, MI | DeWitt, MI | United States |
| Population | 25,179 | 4,755 | 329,725,481 |
| Female Population | 51.1% | 55.6% | 50.5% |
| Male Population | 48.9% | 44.4% | 49.5% |
| Median Age | 34.1 | 44.8 | 38.4 |
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| Population - 2010 | 21,025 | 4,492 | 309,327,143 |
| Population - 2000 | 22,805 | 4,702 | 285,036,114 |
| Population - 1990 | 20,216 | 3,964 | 251,960,433 |
| Pop. 2000 to Now | 2.0% | 2.8% | 15.6% |
| Pop. 1990 to Now | 15.0% | 21.9% | 30.8% |
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| Population Density | 1,493.7 | 1,676.1 | 93.4 |
| Land Area | 16.9 | 2.8 | 3,531,905.4 |
| Water Area | 0.1 | 0.1 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Okemos, MI | DeWitt, MI | United States |
| Age 0 to 4 | 6.6% | 4.2% | 5.9% |
| Age 5 to 9 | 6.9% | 4.7% | 6.1% |
| Age 10 to 14 | 6.3% | 8.0% | 6.6% |
| Age 15 to 17 | 4.3% | 3.0% | 3.9% |
| Age 18 to 20 | 4.3% | 2.7% | 4.0% |
| Age 21 to 24 | 11.5% | 4.4% | 5.2% |
| Age 25 to 34 | 11.1% | 10.9% | 13.8% |
| Age 35 to 44 | 13.5% | 12.4% | 12.9% |
| Age 45 to 54 | 11.7% | 15.1% | 12.6% |
| Age 55 to 59 | 5.0% | 9.9% | 6.7% |
| Age 60 to 64 | 5.2% | 6.9% | 6.3% |
| Age 65 to 74 | 8.6% | 9.3% | 9.6% |
| Age 75 to 84 | 3.4% | 5.5% | 4.5% |
| Age 85 and over | 1.7% | 2.9% | 1.9% |
| space1 | | | |
| Race | | | |
| | Okemos, MI | DeWitt, MI | United States |
| White | 63.6% | 81.9% | 59.4% |
| Black | 6.0% | 1.1% | 12.2% |
| Asian | 20.0% | 0.5% | 5.6% |
| Native American | 0.5% | 0.5% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.5% | 2.6% | 0.4% |
| Two or More Races | 5.7% | 3.8% | 3.2% |
| Hispanic | 3.7% | 9.6% | 18.4% |
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| Marriage & Family | | | |
| | Okemos, MI | DeWitt, MI | United States |
| Married Population | 52.2% | 63.2% | 49.8% |
| Currently Married | 51.9% | 62.7% | 48.0% |
| Married but Separated | 0.3% | 0.5% | 1.8% |
| Single Population | 47.8% | 36.8% | 50.2% |
| Never Married | 35.6% | 26.6% | 33.8% |
| Divorced | 8.2% | 7.5% | 10.8% |
| Widowed | 4.0% | 2.7% | 5.6% |
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| Household Size | 2.50 | 2.56 | 2.60 |
| Households | 9,902 | 1,855 | 124,010,992 |
| Family Households | 6,010 | 1,343 | 80,755,759 |
| Married couple, w/children | 45.2% | 28.2% | 30.5% |
| Married couple, no children | 38.8% | 55.6% | 42.9% |
| Non Family Households | 3,892 | 512 | 43,255,233 |
| Single householder, w/children | 11.0% | 13.2% | 15.8% |
| Single householder, no children | 4.9% | 3.0% | 10.8% |