| | Montrose, IL | Chatham, IL | United States |
| Population | 222 | 14,245 | 329,725,481 |
| Female Population | 45.5% | 55.0% | 50.5% |
| Male Population | 54.5% | 45.0% | 49.5% |
| Median Age | 35.3 | 35.2 | 38.4 |
| space3 | | | |
| Population - 2010 | 202 | 11,779 | 309,327,143 |
| Population - 2000 | 257 | 8,583 | 285,036,114 |
| Population - 1990 | 306 | 6,074 | 251,960,433 |
| Pop. 2000 to Now | -24.1% | 53.3% | 15.6% |
| Pop. 1990 to Now | -36.3% | 116.6% | 30.8% |
| space4 | | | |
| Population Density | 321.7 | 2,045.5 | 93.4 |
| Land Area | 0.7 | 7.0 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Montrose, IL | Chatham, IL | United States |
| Age 0 to 4 | 9.5% | 7.1% | 5.9% |
| Age 5 to 9 | 4.1% | 9.9% | 6.1% |
| Age 10 to 14 | 4.1% | 8.5% | 6.6% |
| Age 15 to 17 | 3.2% | 5.0% | 3.9% |
| Age 18 to 20 | 9.9% | 3.6% | 4.0% |
| Age 21 to 24 | 3.2% | 3.9% | 5.2% |
| Age 25 to 34 | 15.8% | 11.8% | 13.8% |
| Age 35 to 44 | 8.1% | 17.5% | 12.9% |
| Age 45 to 54 | 10.4% | 11.2% | 12.6% |
| Age 55 to 59 | 6.8% | 5.5% | 6.7% |
| Age 60 to 64 | 7.2% | 4.8% | 6.3% |
| Age 65 to 74 | 7.7% | 6.7% | 9.6% |
| Age 75 to 84 | 6.8% | 3.8% | 4.5% |
| Age 85 and over | 3.6% | 0.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Montrose, IL | Chatham, IL | United States |
| White | 90.1% | 92.6% | 59.4% |
| Black | 0.5% | 1.9% | 12.2% |
| Asian | 0.0% | 1.0% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.1% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 3.2% | 2.9% | 3.2% |
| Hispanic | 6.3% | 1.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Montrose, IL | Chatham, IL | United States |
| Married Population | 61.2% | 56.3% | 49.8% |
| Currently Married | 59.0% | 55.8% | 48.0% |
| Married but Separated | 2.2% | 0.5% | 1.8% |
| Single Population | 38.8% | 43.7% | 50.2% |
| Never Married | 21.3% | 25.7% | 33.8% |
| Divorced | 11.5% | 14.4% | 10.8% |
| Widowed | 6.0% | 3.6% | 5.6% |
| space5 | | | |
| Household Size | 2.34 | 2.71 | 2.60 |
| Households | 95 | 5,257 | 124,010,992 |
| Family Households | 66 | 3,605 | 80,755,759 |
| Married couple, w/children | 33.3% | 45.0% | 30.5% |
| Married couple, no children | 43.9% | 36.0% | 42.9% |
| Non Family Households | 29 | 1,652 | 43,255,233 |
| Single householder, w/children | 12.1% | 14.0% | 15.8% |
| Single householder, no children | 10.6% | 5.1% | 10.8% |