| | Monmouth, IL | Salisbury, NC | United States |
| Population | 8,810 | 35,258 | 329,725,481 |
| Female Population | 52.0% | 49.5% | 50.5% |
| Male Population | 48.0% | 50.5% | 49.5% |
| Median Age | 35.6 | 35.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 9,424 | 33,471 | 309,327,143 |
| Population - 2000 | 9,841 | 26,462 | 285,036,114 |
| Population - 1990 | 9,489 | 23,087 | 251,960,433 |
| Pop. 2000 to Now | -10.6% | 27.8% | 15.6% |
| Pop. 1990 to Now | -7.3% | 46.5% | 30.8% |
| space4 | | | |
| Population Density | 2,083.7 | 1,585.6 | 93.4 |
| Land Area | 4.2 | 22.2 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Monmouth, IL | Salisbury, NC | United States |
| Age 0 to 4 | 4.9% | 6.0% | 5.9% |
| Age 5 to 9 | 6.5% | 7.0% | 6.1% |
| Age 10 to 14 | 7.8% | 6.4% | 6.6% |
| Age 15 to 17 | 4.8% | 3.7% | 3.9% |
| Age 18 to 20 | 8.2% | 6.1% | 4.0% |
| Age 21 to 24 | 7.3% | 6.0% | 5.2% |
| Age 25 to 34 | 9.9% | 13.8% | 13.8% |
| Age 35 to 44 | 10.0% | 10.8% | 12.9% |
| Age 45 to 54 | 11.7% | 12.1% | 12.6% |
| Age 55 to 59 | 6.2% | 5.8% | 6.7% |
| Age 60 to 64 | 6.3% | 5.5% | 6.3% |
| Age 65 to 74 | 9.2% | 9.8% | 9.6% |
| Age 75 to 84 | 4.8% | 4.9% | 4.5% |
| Age 85 and over | 2.4% | 2.2% | 1.9% |
| space1 | | | |
| Race | | | |
| | Monmouth, IL | Salisbury, NC | United States |
| White | 70.4% | 48.9% | 59.4% |
| Black | 6.6% | 36.5% | 12.2% |
| Asian | 2.5% | 1.0% | 5.6% |
| Native American | 0.5% | 0.3% | 0.6% |
| Hawaiian, Pacific Islander | 0.1% | 0.0% | 0.2% |
| Other | 0.6% | 0.0% | 0.4% |
| Two or More Races | 1.9% | 2.8% | 3.2% |
| Hispanic | 17.4% | 10.5% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Monmouth, IL | Salisbury, NC | United States |
| Married Population | 39.0% | 41.5% | 49.8% |
| Currently Married | 38.0% | 38.8% | 48.0% |
| Married but Separated | 1.0% | 2.7% | 1.8% |
| Single Population | 61.0% | 58.5% | 50.2% |
| Never Married | 41.3% | 39.6% | 33.8% |
| Divorced | 13.6% | 11.6% | 10.8% |
| Widowed | 6.1% | 7.3% | 5.6% |
| space5 | | | |
| Household Size | 2.33 | 2.42 | 2.60 |
| Households | 3,345 | 13,143 | 124,010,992 |
| Family Households | 2,177 | 7,966 | 80,755,759 |
| Married couple, w/children | 20.9% | 24.1% | 30.5% |
| Married couple, no children | 38.8% | 35.1% | 42.9% |
| Non Family Households | 1,168 | 5,177 | 43,255,233 |
| Single householder, w/children | 27.9% | 29.5% | 15.8% |
| Single householder, no children | 12.4% | 11.3% | 10.8% |