St. Mary is located in Hancock County, Illinois. St. Mary has a 2025 population of 538 . St. Mary is currently declining at a rate of -0.92% annually and its population has decreased by -3.93% since the most recent census, which recorded a population of 560 in 2020.
The average household income in St. Mary is $65,608 with a poverty rate of 21.93%. The median age in St. Mary is 52.8 years: 49.4 years for males, and 55.2 years for females. For every 100 females there are 128.0 males.
Data after 2023 is projected based on recent change
The racial composition of St. Mary includes 95.76% White, and smaller percentages for Black or African American, Two or more races, other race and multiracial populations.
White (95.76%)
Black or African American (2.05%)
Two or more races (1.75%)
Other race (0.44%)
Race | Population | Percentage (of total) |
|---|---|---|
| White | 655 | 95.76% |
| Black or African American | 14 | 2.05% |
| Two or more races | 12 | 1.75% |
| Other race | 3 | 0.44% |
Married
Widowed
Divorced
Separated
Never Married
St. Mary's average per capita income is $40,703. Household income levels show a median of $52,727. The poverty rate stands at 21.93%.
Name | Median | Mean |
|---|---|---|
| Married Families | $93,600 | - |
| Families | $80,833 | $80,299 |
| Households | $52,727 | $65,608 |
| Non Families | $24,375 | $32,440 |
Average Income
Median Household Income
Poverty Rate