| | Tama, IA | Greenfield, IA | United States |
| Population | 3,072 | 1,671 | 329,725,481 |
| Female Population | 49.8% | 46.6% | 50.5% |
| Male Population | 50.2% | 53.4% | 49.5% |
| Median Age | 32.9 | 53.5 | 38.4 |
| space3 | | | |
| Population - 2010 | 2,869 | 1,986 | 309,327,143 |
| Population - 2000 | 2,731 | 2,129 | 285,036,114 |
| Population - 1990 | 2,697 | 2,074 | 251,960,433 |
| Pop. 2000 to Now | -0.3% | -14.9% | 15.6% |
| Pop. 1990 to Now | 1.0% | -12.6% | 30.8% |
| space4 | | | |
| Population Density | 1,042.8 | 921.2 | 93.4 |
| Land Area | 2.9 | 1.8 | 3,531,905.4 |
| Water Area | 0.1 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Tama, IA | Greenfield, IA | United States |
| Age 0 to 4 | 5.7% | 3.8% | 5.9% |
| Age 5 to 9 | 8.5% | 5.4% | 6.1% |
| Age 10 to 14 | 15.0% | 4.0% | 6.6% |
| Age 15 to 17 | 3.5% | 2.9% | 3.9% |
| Age 18 to 20 | 3.2% | 1.7% | 4.0% |
| Age 21 to 24 | 2.1% | 5.6% | 5.2% |
| Age 25 to 34 | 14.2% | 11.6% | 13.8% |
| Age 35 to 44 | 14.3% | 6.7% | 12.9% |
| Age 45 to 54 | 9.0% | 9.9% | 12.6% |
| Age 55 to 59 | 4.8% | 6.8% | 6.7% |
| Age 60 to 64 | 4.3% | 10.4% | 6.3% |
| Age 65 to 74 | 6.5% | 13.2% | 9.6% |
| Age 75 to 84 | 6.2% | 10.8% | 4.5% |
| Age 85 and over | 2.6% | 7.2% | 1.9% |
| space1 | | | |
| Race | | | |
| | Tama, IA | Greenfield, IA | United States |
| White | 54.8% | 97.4% | 59.4% |
| Black | 2.2% | 1.5% | 12.2% |
| Asian | 0.0% | 0.0% | 5.6% |
| Native American | 4.1% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 2.7% | 1.1% | 3.2% |
| Hispanic | 36.2% | 0.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Tama, IA | Greenfield, IA | United States |
| Married Population | 58.1% | 43.9% | 49.8% |
| Currently Married | 55.0% | 43.4% | 48.0% |
| Married but Separated | 3.1% | 0.5% | 1.8% |
| Single Population | 42.0% | 56.1% | 50.2% |
| Never Married | 24.8% | 26.5% | 33.8% |
| Divorced | 11.1% | 15.2% | 10.8% |
| Widowed | 6.0% | 14.4% | 5.6% |
| space5 | | | |
| Household Size | 2.83 | 1.81 | 2.60 |
| Households | 1,070 | 901 | 124,010,992 |
| Family Households | 774 | 356 | 80,755,759 |
| Married couple, w/children | 32.7% | 24.4% | 30.5% |
| Married couple, no children | 36.0% | 53.7% | 42.9% |
| Non Family Households | 296 | 545 | 43,255,233 |
| Single householder, w/children | 26.4% | 15.7% | 15.8% |
| Single householder, no children | 4.9% | 6.2% | 10.8% |