| | Plymouth, OH | Erwin, TN | United States |
| Population | 1,727 | 6,052 | 329,725,481 |
| Female Population | 53.0% | 48.2% | 50.5% |
| Male Population | 47.0% | 51.8% | 49.5% |
| Median Age | 36.5 | 45 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,855 | 6,077 | 309,327,143 |
| Population - 2000 | 1,852 | 5,610 | 285,036,114 |
| Population - 1990 | 1,942 | 5,015 | 251,960,433 |
| Pop. 2000 to Now | -3.4% | 4.4% | 15.6% |
| Pop. 1990 to Now | -7.9% | 16.7% | 30.8% |
| space4 | | | |
| Population Density | 680.7 | 1,466.8 | 93.4 |
| Land Area | 2.5 | 4.1 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Plymouth, OH | Erwin, TN | United States |
| Age 0 to 4 | 10.5% | 1.5% | 5.9% |
| Age 5 to 9 | 5.1% | 5.2% | 6.1% |
| Age 10 to 14 | 5.7% | 5.5% | 6.6% |
| Age 15 to 17 | 4.9% | 5.8% | 3.9% |
| Age 18 to 20 | 4.0% | 2.3% | 4.0% |
| Age 21 to 24 | 4.9% | 7.4% | 5.2% |
| Age 25 to 34 | 13.8% | 8.7% | 13.8% |
| Age 35 to 44 | 9.6% | 13.8% | 12.9% |
| Age 45 to 54 | 16.6% | 16.4% | 12.6% |
| Age 55 to 59 | 5.0% | 4.5% | 6.7% |
| Age 60 to 64 | 3.1% | 6.8% | 6.3% |
| Age 65 to 74 | 9.1% | 10.2% | 9.6% |
| Age 75 to 84 | 6.9% | 7.8% | 4.5% |
| Age 85 and over | 0.8% | 4.1% | 1.9% |
| space1 | | | |
| Race | | | |
| | Plymouth, OH | Erwin, TN | United States |
| White | 94.2% | 87.7% | 59.4% |
| Black | 0.4% | 0.3% | 12.2% |
| Asian | 0.0% | 0.0% | 5.6% |
| Native American | 0.4% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 2.2% | 1.3% | 3.2% |
| Hispanic | 2.8% | 10.6% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Plymouth, OH | Erwin, TN | United States |
| Married Population | 51.0% | 54.1% | 49.8% |
| Currently Married | 47.5% | 52.1% | 48.0% |
| Married but Separated | 3.5% | 1.9% | 1.8% |
| Single Population | 49.0% | 45.9% | 50.2% |
| Never Married | 32.7% | 25.7% | 33.8% |
| Divorced | 12.3% | 12.8% | 10.8% |
| Widowed | 4.0% | 7.4% | 5.6% |
| space5 | | | |
| Household Size | 2.63 | 2.24 | 2.60 |
| Households | 656 | 2,600 | 124,010,992 |
| Family Households | 471 | 1,757 | 80,755,759 |
| Married couple, w/children | 21.2% | 29.4% | 30.5% |
| Married couple, no children | 44.6% | 48.6% | 42.9% |
| Non Family Households | 185 | 843 | 43,255,233 |
| Single householder, w/children | 21.2% | 12.6% | 15.8% |
| Single householder, no children | 13.0% | 9.4% | 10.8% |