| | Rockland, MA | Rifle, CO | United States |
| Population | 17,774 | 10,325 | 329,725,481 |
| Female Population | 53.5% | 47.9% | 50.5% |
| Male Population | 46.5% | 52.1% | 49.5% |
| Median Age | 39.5 | 31.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 17,500 | 9,344 | 309,327,143 |
| Population - 2000 | 17,670 | 6,784 | 285,036,114 |
| Population - 1990 | 16,123 | 4,636 | 251,960,433 |
| Pop. 2000 to Now | 1.8% | 44.1% | 15.6% |
| Pop. 1990 to Now | 11.6% | 110.9% | 30.8% |
| space4 | | | |
| Population Density | 1,772.6 | 1,459.4 | 93.4 |
| Land Area | 10.0 | 7.1 | 3,531,905.4 |
| Water Area | 0.1 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Rockland, MA | Rifle, CO | United States |
| Age 0 to 4 | 6.8% | 9.1% | 5.9% |
| Age 5 to 9 | 5.8% | 7.0% | 6.1% |
| Age 10 to 14 | 6.6% | 9.7% | 6.6% |
| Age 15 to 17 | 3.0% | 2.8% | 3.9% |
| Age 18 to 20 | 2.5% | 5.0% | 4.0% |
| Age 21 to 24 | 5.4% | 8.0% | 5.2% |
| Age 25 to 34 | 14.2% | 14.9% | 13.8% |
| Age 35 to 44 | 12.7% | 13.0% | 12.9% |
| Age 45 to 54 | 13.5% | 11.2% | 12.6% |
| Age 55 to 59 | 7.6% | 5.6% | 6.7% |
| Age 60 to 64 | 8.2% | 4.6% | 6.3% |
| Age 65 to 74 | 9.1% | 5.7% | 9.6% |
| Age 75 to 84 | 3.1% | 2.0% | 4.5% |
| Age 85 and over | 1.5% | 1.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Rockland, MA | Rifle, CO | United States |
| White | 87.7% | 59.0% | 59.4% |
| Black | 2.7% | 0.1% | 12.2% |
| Asian | 0.9% | 0.5% | 5.6% |
| Native American | 0.2% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.3% | 0.2% |
| Other | 2.6% | 0.1% | 0.4% |
| Two or More Races | 3.1% | 4.0% | 3.2% |
| Hispanic | 2.8% | 36.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Rockland, MA | Rifle, CO | United States |
| Married Population | 49.9% | 58.5% | 49.8% |
| Currently Married | 49.4% | 57.9% | 48.0% |
| Married but Separated | 0.5% | 0.6% | 1.8% |
| Single Population | 50.1% | 41.5% | 50.2% |
| Never Married | 34.4% | 26.3% | 33.8% |
| Divorced | 9.9% | 10.1% | 10.8% |
| Widowed | 5.9% | 5.1% | 5.6% |
| space5 | | | |
| Household Size | 2.64 | 2.99 | 2.60 |
| Households | 6,654 | 3,420 | 124,010,992 |
| Family Households | 4,548 | 2,652 | 80,755,759 |
| Married couple, w/children | 37.6% | 43.4% | 30.5% |
| Married couple, no children | 37.4% | 36.8% | 42.9% |
| Non Family Households | 2,106 | 768 | 43,255,233 |
| Single householder, w/children | 9.1% | 10.8% | 15.8% |
| Single householder, no children | 15.8% | 8.9% | 10.8% |