| Place Name | St. Mary's |
| Place Type | Census Designated Place |
| ZIP Code(s) | 80452 |
| County | Clear Creek County |
| Area Code(s) | 303,720 |
| Timezone | Mountain Daylight Time (MDT) |
| Population (2022) | 124 |
| Population Growth Rate (2010-19) | 17.67% |
| Majority Ethnicity | White 93.03% |
| Metro/Micro Stats Area | Denver-Aurora-Lakewood, CO |
| US Congressional District(s) | Colorado 2nd |
| State House Districts | 13 |
| State Senate Districts | 2 |
| Race/Ethnicy | Percentage of Population (2021) |
|---|---|
| White | 93.03% |
| African American | 0% |
| Hispanic | 0% |
| Asian | 0% |
| Native American | 0% |
| Hawaiin/Pacific Islander | 6.97% |