St. Mary: Demographics & People
Census counts 147 people in St. Mary, in 48 households. Population shrank 30.0% from 210 (2022) to 147 (2024). Median age 34.6 years. (5.8y younger than Marion County; 4.6y younger than Kentucky). Children under 18 are 39% of the population. Population is 87% White (non-Hispanic) and 2% Black. The community is relatively homogeneous (Simpson index 0.02). 73% of households are family-led. County health: 41% adult obesity, 23% smoke.
- 3.1 people per household.
- 27% non-family households (singles, roommates).
Population & Trend
Population shrank 30.0% from 210 (2022) to 147 (2024). Estimated 2026 population: ~106 (extrapolated at -15.0%/yr trend). Census Bureau Vintage estimate: 63.
| Census data vintage | 2024 |
|---|---|
| Population | 19,581 people |
| Annual growth rate · Population change | -30.0% |
| Annual growth rate · Population (2022) | 210 |
| Annual growth rate · Population (2024) | 147 |
| Annual growth rate · Trend category | shrinking |
| Population | 147 people |
| Population Estimate | 63 |
Sources: Census ACS 5-Year 2023, Table B01003 · Refreshed 2026-04-12
Age Distribution
Median age 34.6y is 4.3 years younger than the U.S. median (38.9y). Children under 18 make up 39% — above the U.S. share of ~22%.
| Age Summary · Median age | 34.6 years (vs Kentucky 39.2y) |
|---|---|
| Age Summary · Children Pct | 38.8% |
| Age Summary · Character | young professional |
| Population under 18 | 57 |
| Median age | 34.6 years (vs Kentucky 39.2y) |
Sources: Census ACS 5-Year 2023 · Refreshed 2026-04-12
Race, Ethnicity & Diversity
Of 147 residents, race / ethnicity breaks down by Census ACS counts (a person can identify with one or more groups). The Simpson diversity index is 0.02 (0 = single group, 1 = perfectly even distribution); this is read as relatively homogeneous.
| White residents | 196 |
|---|---|
| Black residents | 2 |
| Diversity Index · Diversity index (Simpson) | 2.0% |
| Diversity Index · Diversity label | relatively homogeneous |
| Diversity Index · Groups counted | 2 |
| Diversity Index · Largest group share | 99.0% |
| Black population | 2.0% |
| White (non-Hispanic) population | 87.1% |
Sources: Census ACS 5-Year 2023 · Refreshed 2026-04-12
Ancestry
Self-reported ancestry from Census ACS — what residents report as their ethnic origin, separate from race. Counts can exceed population because people can list multiple ancestries.
Top (5)
Citizenship & Origin
Where residents were born and their citizenship status (Census ACS).
| Residents born in this state | 147 |
|---|---|
| Share born in this state | 100.0% |
| Total foreign-born residents | 383 |
Households & Family Composition
48 households. Averaging 2.9 people each — larger than the U.S. average of 2.5. 73% are family households — above the U.S. share of ~65%. Of 48 families, 31% are married couples with children.
| Children under 18 | 50 |
|---|---|
| Total families | 48 |
| Married couples with children | 15 |
| Average household size | 2.92 |
| Women who gave birth (past year) | 30.6% |
| Grandparents living with grandchildren | 276 |
| Grandparents responsible for grandchildren | 95 |
| Family households | 35 households |
| Households that are families | 72.9% |
| Total households | 48 households |
Sources: Census ACS 5-Year 2023 · Refreshed 2026-04-12
Residential Stability & Migration
How long residents have lived here and where they came from. 17.8% moved within the county in the past year — the U.S. baseline is roughly 8–10%.
| Moved within the county (past year) | 17.8% |
|---|---|
| Migration · People moving in (annual) | 17,099 |
| Migration · People moving out (annual) | 17,098 |
| Migration · Net migration (in − out) | 1 |
| Migration · Population growing | Yes |
| Migration · Year | 2022-2023 |
Sources: IRS SOI Migration 2021-2022 · Refreshed 2026-04-12
Disability
Census ACS measures self-reported functional limitations — vision, hearing, mobility, cognitive, self-care, or independent-living. The U.S. baseline disability rate is about 12–13%; rates trend higher with median age.
| Residents with a disability | 31 |
|---|---|
| Disability rate | 16.8% |
Other
| Congressional District · District | 1 |
|---|---|
| Congressional District · Formatted | KY-01 |
| Congressional District · Congress | 118th |
| Cdc Birth Rate · Fips | 21,155 |
| Cdc Birth Rate · State Fips | 21 |
| Cdc Birth Rate · County Fips | 155 |
| Cdc Birth Rate · County | Marion |
| Cdc Birth Rate · Birth Rate | 32.1% |
| Cdc Birth Rate · Lower Ci | 26.00 |
| Cdc Birth Rate · Upper Ci | 39.10 |
| Cdc Mortality · Fips | 21,155 |
| Cdc Mortality · County | Marion County |
| Cdc Mortality · Urban Rural | Noncore |
| Cdc Mortality · Total Deaths 2020 2023 | 719 |
| Cdc Vaccination · Fips | 21,155 |
| Cdc Vaccination · County | Marion County |
| Cdc Vaccination · Dose1 Pop Pct | 57.5% |
| Cdc Vaccination · Series Complete Pct | 51.9% |
| Cdc Vaccination · Booster Pct | 49.3% |
| Cdc Vaccination · Population 2019 | 19,273 |
| Cdc Vaccination · Metro Status | Non-metro |
| Family Score · Score | 5.50 |
| Family Score · Schools | 9 |
| Family Score · Children Pct | 38.8% |
| Family Score · Rating | good |
| Town Summary · Key Facts | population 147, shrinking, young professional, working-class, mixed |
| Town Summary · Population | 147 people |
| Town Summary · County | Marion County |
Sources: Census place-to-CD118 crosswalk (place_fips) · federal dataset cascade