| | Lunenburg, MA | Marlborough, MA | United States |
| Population | 11,627 | 41,505 | 329,725,481 |
| Female Population | 49.6% | 51.3% | 50.5% |
| Male Population | 50.5% | 48.7% | 49.5% |
| Median Age | 42.7 | 39.2 | 38.4 |
| space3 | | | |
| Population - 2010 | 10,084 | 38,584 | 309,327,143 |
| Population - 2000 | 9,401 | 36,255 | 285,036,114 |
| Population - 1990 | 9,117 | 31,813 | 251,960,433 |
| Pop. 2000 to Now | 25.6% | 8.4% | 15.6% |
| Pop. 1990 to Now | 29.5% | 23.5% | 30.8% |
| space4 | | | |
| Population Density | 439.5 | 1,989.7 | 93.4 |
| Land Area | 26.5 | 20.9 | 3,531,905.4 |
| Water Area | 1.3 | 1.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Lunenburg, MA | Marlborough, MA | United States |
| Age 0 to 4 | 5.0% | 6.6% | 5.9% |
| Age 5 to 9 | 6.0% | 5.5% | 6.1% |
| Age 10 to 14 | 7.2% | 5.0% | 6.6% |
| Age 15 to 17 | 4.5% | 2.6% | 3.9% |
| Age 18 to 20 | 3.7% | 2.3% | 4.0% |
| Age 21 to 24 | 3.7% | 4.6% | 5.2% |
| Age 25 to 34 | 12.0% | 16.4% | 13.8% |
| Age 35 to 44 | 11.0% | 14.4% | 12.9% |
| Age 45 to 54 | 14.0% | 13.3% | 12.6% |
| Age 55 to 59 | 9.1% | 8.1% | 6.7% |
| Age 60 to 64 | 7.8% | 6.9% | 6.3% |
| Age 65 to 74 | 10.5% | 8.6% | 9.6% |
| Age 75 to 84 | 4.2% | 3.8% | 4.5% |
| Age 85 and over | 1.2% | 1.8% | 1.9% |
| space1 | | | |
| Race | | | |
| | Lunenburg, MA | Marlborough, MA | United States |
| White | 87.5% | 64.4% | 59.4% |
| Black | 1.0% | 3.4% | 12.2% |
| Asian | 1.1% | 5.2% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 1.4% | 4.1% | 0.4% |
| Two or More Races | 2.4% | 6.6% | 3.2% |
| Hispanic | 6.6% | 16.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Lunenburg, MA | Marlborough, MA | United States |
| Married Population | 62.6% | 52.0% | 49.8% |
| Currently Married | 61.1% | 50.1% | 48.0% |
| Married but Separated | 1.5% | 2.0% | 1.8% |
| Single Population | 37.4% | 48.0% | 50.2% |
| Never Married | 24.3% | 33.1% | 33.8% |
| Divorced | 8.5% | 10.9% | 10.8% |
| Widowed | 4.6% | 4.0% | 5.6% |
| space5 | | | |
| Household Size | 2.62 | 2.39 | 2.60 |
| Households | 4,432 | 17,147 | 124,010,992 |
| Family Households | 3,281 | 10,313 | 80,755,759 |
| Married couple, w/children | 30.7% | 33.3% | 30.5% |
| Married couple, no children | 54.6% | 42.6% | 42.9% |
| Non Family Households | 1,151 | 6,834 | 43,255,233 |
| Single householder, w/children | 9.7% | 12.3% | 15.8% |
| Single householder, no children | 5.0% | 11.7% | 10.8% |