| | Northfield, MA | Santa Paula, CA | United States |
| Population | 2,899 | 30,741 | 329,725,481 |
| Female Population | 50.2% | 50.5% | 50.5% |
| Male Population | 49.8% | 49.5% | 49.5% |
| Median Age | 47.6 | 33.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 3,030 | 29,700 | 309,327,143 |
| Population - 2000 | 2,951 | 28,598 | 285,036,114 |
| Population - 1990 | 2,838 | 25,062 | 251,960,433 |
| Pop. 2000 to Now | 0.2% | 5.8% | 15.6% |
| Pop. 1990 to Now | 4.2% | 20.7% | 30.8% |
| space4 | | | |
| Population Density | 84.6 | 6,771.2 | 93.4 |
| Land Area | 34.3 | 4.5 | 3,531,905.4 |
| Water Area | 1.1 | 0.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Northfield, MA | Santa Paula, CA | United States |
| Age 0 to 4 | 2.9% | 7.3% | 5.9% |
| Age 5 to 9 | 4.2% | 7.4% | 6.1% |
| Age 10 to 14 | 5.6% | 8.1% | 6.6% |
| Age 15 to 17 | 6.3% | 5.4% | 3.9% |
| Age 18 to 20 | 4.1% | 3.9% | 4.0% |
| Age 21 to 24 | 5.1% | 6.2% | 5.2% |
| Age 25 to 34 | 6.3% | 13.3% | 13.8% |
| Age 35 to 44 | 13.6% | 14.4% | 12.9% |
| Age 45 to 54 | 13.3% | 12.2% | 12.6% |
| Age 55 to 59 | 9.3% | 4.4% | 6.7% |
| Age 60 to 64 | 9.4% | 4.0% | 6.3% |
| Age 65 to 74 | 11.8% | 7.9% | 9.6% |
| Age 75 to 84 | 3.3% | 3.3% | 4.5% |
| Age 85 and over | 4.7% | 2.1% | 1.9% |
| space1 | | | |
| Race | | | |
| | Northfield, MA | Santa Paula, CA | United States |
| White | 89.8% | 14.3% | 59.4% |
| Black | 0.1% | 0.5% | 12.2% |
| Asian | 0.2% | 0.8% | 5.6% |
| Native American | 0.0% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.3% | 0.4% | 0.4% |
| Two or More Races | 4.1% | 1.0% | 3.2% |
| Hispanic | 5.5% | 82.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Northfield, MA | Santa Paula, CA | United States |
| Married Population | 50.7% | 49.1% | 49.8% |
| Currently Married | 47.9% | 46.8% | 48.0% |
| Married but Separated | 2.7% | 2.2% | 1.8% |
| Single Population | 49.3% | 50.9% | 50.2% |
| Never Married | 29.4% | 38.1% | 33.8% |
| Divorced | 13.0% | 7.9% | 10.8% |
| Widowed | 6.9% | 4.9% | 5.6% |
| space5 | | | |
| Household Size | 2.36 | 3.41 | 2.60 |
| Households | 1,213 | 8,972 | 124,010,992 |
| Family Households | 916 | 6,832 | 80,755,759 |
| Married couple, w/children | 20.5% | 34.1% | 30.5% |
| Married couple, no children | 44.7% | 36.7% | 42.9% |
| Non Family Households | 297 | 2,140 | 43,255,233 |
| Single householder, w/children | 13.0% | 15.5% | 15.8% |
| Single householder, no children | 21.8% | 13.7% | 10.8% |