| | Riverside, CT | Plymouth, MA | United States |
| Population | 9,133 | 60,987 | 329,725,481 |
| Female Population | 51.5% | 50.8% | 50.5% |
| Male Population | 48.5% | 49.2% | 49.5% |
| Median Age | 40.8 | 47.9 | 38.4 |
| space3 | | | |
| Population - 2010 | 8,413 | 56,654 | 309,327,143 |
| Population - 2000 | 8,080 | 51,701 | 285,036,114 |
| Population - 1990 | 8,062 | 45,608 | 251,960,433 |
| Pop. 2000 to Now | 3.5% | 21.2% | 15.6% |
| Pop. 1990 to Now | 3.7% | 37.4% | 30.8% |
| space4 | | | |
| Population Density | 3,772.4 | 632.3 | 93.4 |
| Land Area | 2.4 | 96.4 | 3,531,905.4 |
| Water Area | 0.8 | 37.5 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Riverside, CT | Plymouth, MA | United States |
| Age 0 to 4 | 5.0% | 4.2% | 5.9% |
| Age 5 to 9 | 9.5% | 5.0% | 6.1% |
| Age 10 to 14 | 9.7% | 4.7% | 6.6% |
| Age 15 to 17 | 7.8% | 3.1% | 3.9% |
| Age 18 to 20 | 2.9% | 2.3% | 4.0% |
| Age 21 to 24 | 3.6% | 3.8% | 5.2% |
| Age 25 to 34 | 5.8% | 12.3% | 13.8% |
| Age 35 to 44 | 12.1% | 11.0% | 12.9% |
| Age 45 to 54 | 17.8% | 13.2% | 12.6% |
| Age 55 to 59 | 7.6% | 8.6% | 6.7% |
| Age 60 to 64 | 5.2% | 8.7% | 6.3% |
| Age 65 to 74 | 6.4% | 14.6% | 9.6% |
| Age 75 to 84 | 4.8% | 6.2% | 4.5% |
| Age 85 and over | 1.7% | 2.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Riverside, CT | Plymouth, MA | United States |
| White | 63.5% | 91.2% | 59.4% |
| Black | 1.8% | 1.3% | 12.2% |
| Asian | 16.5% | 0.9% | 5.6% |
| Native American | 0.4% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.2% | 0.8% | 0.4% |
| Two or More Races | 4.2% | 3.0% | 3.2% |
| Hispanic | 13.4% | 2.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Riverside, CT | Plymouth, MA | United States |
| Married Population | 62.1% | 57.5% | 49.8% |
| Currently Married | 61.9% | 56.2% | 48.0% |
| Married but Separated | 0.2% | 1.3% | 1.8% |
| Single Population | 37.9% | 42.5% | 50.2% |
| Never Married | 28.2% | 27.1% | 33.8% |
| Divorced | 5.9% | 9.4% | 10.8% |
| Widowed | 3.8% | 6.0% | 5.6% |
| space5 | | | |
| Household Size | 3.11 | 2.37 | 2.60 |
| Households | 2,936 | 24,985 | 124,010,992 |
| Family Households | 2,331 | 17,004 | 80,755,759 |
| Married couple, w/children | 53.0% | 25.8% | 30.5% |
| Married couple, no children | 35.7% | 56.0% | 42.9% |
| Non Family Households | 605 | 7,981 | 43,255,233 |
| Single householder, w/children | 6.4% | 9.7% | 15.8% |
| Single householder, no children | 4.9% | 8.4% | 10.8% |