| | Buchanan, MI | Opelika, AL | United States |
| Population | 4,286 | 30,810 | 329,725,481 |
| Female Population | 55.9% | 51.2% | 50.5% |
| Male Population | 44.1% | 48.8% | 49.5% |
| Median Age | 37.9 | 40.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 4,444 | 26,486 | 309,327,143 |
| Population - 2000 | 4,681 | 23,498 | 285,036,114 |
| Population - 1990 | 4,992 | 22,122 | 251,960,433 |
| Pop. 2000 to Now | -9.8% | 32.5% | 15.6% |
| Pop. 1990 to Now | -15.4% | 40.7% | 30.8% |
| space4 | | | |
| Population Density | 1,699.4 | 516.5 | 93.4 |
| Land Area | 2.5 | 59.7 | 3,531,905.4 |
| Water Area | 0.1 | 0.9 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Buchanan, MI | Opelika, AL | United States |
| Age 0 to 4 | 5.2% | 7.1% | 5.9% |
| Age 5 to 9 | 3.8% | 4.8% | 6.1% |
| Age 10 to 14 | 10.2% | 6.2% | 6.6% |
| Age 15 to 17 | 3.8% | 3.1% | 3.9% |
| Age 18 to 20 | 1.8% | 3.7% | 4.0% |
| Age 21 to 24 | 10.3% | 5.0% | 5.2% |
| Age 25 to 34 | 13.6% | 14.9% | 13.8% |
| Age 35 to 44 | 7.8% | 10.5% | 12.9% |
| Age 45 to 54 | 16.0% | 13.2% | 12.6% |
| Age 55 to 59 | 3.4% | 7.0% | 6.7% |
| Age 60 to 64 | 6.6% | 6.1% | 6.3% |
| Age 65 to 74 | 8.7% | 11.5% | 9.6% |
| Age 75 to 84 | 5.4% | 5.1% | 4.5% |
| Age 85 and over | 3.4% | 1.8% | 1.9% |
| space1 | | | |
| Race | | | |
| | Buchanan, MI | Opelika, AL | United States |
| White | 88.8% | 53.0% | 59.4% |
| Black | 4.1% | 36.6% | 12.2% |
| Asian | 0.5% | 2.5% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.3% | 0.0% | 0.4% |
| Two or More Races | 5.0% | 1.6% | 3.2% |
| Hispanic | 1.2% | 6.3% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Buchanan, MI | Opelika, AL | United States |
| Married Population | 47.6% | 46.4% | 49.8% |
| Currently Married | 46.2% | 45.0% | 48.0% |
| Married but Separated | 1.5% | 1.4% | 1.8% |
| Single Population | 52.4% | 53.6% | 50.2% |
| Never Married | 31.8% | 35.3% | 33.8% |
| Divorced | 12.1% | 13.1% | 10.8% |
| Widowed | 8.5% | 5.2% | 5.6% |
| space5 | | | |
| Household Size | 2.45 | 2.49 | 2.60 |
| Households | 1,747 | 12,155 | 124,010,992 |
| Family Households | 1,039 | 7,534 | 80,755,759 |
| Married couple, w/children | 23.6% | 24.3% | 30.5% |
| Married couple, no children | 47.2% | 43.7% | 42.9% |
| Non Family Households | 708 | 4,621 | 43,255,233 |
| Single householder, w/children | 23.9% | 18.9% | 15.8% |
| Single householder, no children | 5.4% | 13.1% | 10.8% |