| | Manhattan, MT | Campbell, CA | United States |
| Population | 1,884 | 43,954 | 329,725,481 |
| Female Population | 41.2% | 49.9% | 50.5% |
| Male Population | 58.8% | 50.1% | 49.5% |
| Median Age | 41.5 | 39.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,516 | 40,672 | 309,327,143 |
| Population - 2000 | 1,396 | 38,138 | 285,036,114 |
| Population - 1990 | 1,034 | 37,256 | 251,960,433 |
| Pop. 2000 to Now | 37.3% | 11.3% | 15.6% |
| Pop. 1990 to Now | 85.4% | 13.9% | 30.8% |
| space4 | | | |
| Population Density | 1,077.8 | 7,226.9 | 93.4 |
| Land Area | 1.7 | 6.1 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Manhattan, MT | Campbell, CA | United States |
| Age 0 to 4 | 4.7% | 6.8% | 5.9% |
| Age 5 to 9 | 11.1% | 6.5% | 6.1% |
| Age 10 to 14 | 10.7% | 5.4% | 6.6% |
| Age 15 to 17 | 4.2% | 3.2% | 3.9% |
| Age 18 to 20 | 0.0% | 1.9% | 4.0% |
| Age 21 to 24 | 2.5% | 2.8% | 5.2% |
| Age 25 to 34 | 4.5% | 15.1% | 13.8% |
| Age 35 to 44 | 14.8% | 16.4% | 12.9% |
| Age 45 to 54 | 12.2% | 13.4% | 12.6% |
| Age 55 to 59 | 10.4% | 8.1% | 6.7% |
| Age 60 to 64 | 6.7% | 6.2% | 6.3% |
| Age 65 to 74 | 11.0% | 8.0% | 9.6% |
| Age 75 to 84 | 2.5% | 3.4% | 4.5% |
| Age 85 and over | 4.7% | 2.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Manhattan, MT | Campbell, CA | United States |
| White | 94.7% | 48.3% | 59.4% |
| Black | 0.0% | 2.2% | 12.2% |
| Asian | 0.0% | 24.9% | 5.6% |
| Native American | 1.2% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.6% | 0.4% |
| Two or More Races | 3.0% | 5.3% | 3.2% |
| Hispanic | 1.1% | 18.4% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Manhattan, MT | Campbell, CA | United States |
| Married Population | 64.7% | 55.3% | 49.8% |
| Currently Married | 64.5% | 54.2% | 48.0% |
| Married but Separated | 0.2% | 1.1% | 1.8% |
| Single Population | 35.3% | 44.7% | 50.2% |
| Never Married | 18.4% | 31.0% | 33.8% |
| Divorced | 11.6% | 9.1% | 10.8% |
| Widowed | 5.4% | 4.6% | 5.6% |
| space5 | | | |
| Household Size | 2.48 | 2.52 | 2.60 |
| Households | 756 | 17,346 | 124,010,992 |
| Family Households | 475 | 11,128 | 80,755,759 |
| Married couple, w/children | 55.2% | 35.6% | 30.5% |
| Married couple, no children | 38.9% | 42.2% | 42.9% |
| Non Family Households | 281 | 6,218 | 43,255,233 |
| Single householder, w/children | 4.2% | 13.1% | 15.8% |
| Single householder, no children | 1.7% | 9.1% | 10.8% |