St. Marys: Demographics & People
St. Marys's population stands at 12,529 people, in 5,692 households. Population shrank 0.7% from 12,612 (2022) to 12,529 (2024). Median age 51.6 years. (3.2y older than Elk County; 10.4y older than Pennsylvania). Children under 18 are 16% of the population. Population is 94% White (non-Hispanic) and 2% Hispanic or Latino. 61% of households are family-led. County health: 38% adult obesity, 18% smoke.
- 2.2 people per household.
- 39% non-family households (singles, roommates).
Population & Trend
Population shrank 0.7% from 12,612 (2022) to 12,529 (2024). Estimated 2026 population: ~12,446 (extrapolated at -0.3%/yr trend). Census Bureau Vintage estimate: 12,336.
| Census data vintage | 2024 |
|---|---|
| Population | 30,990 people |
| Annual growth rate · Population change | -0.7% |
| Annual growth rate · Population (2022) | 12,612 |
| Annual growth rate · Population (2024) | 12,529 |
| Annual growth rate · Trend category | stable |
| Population | 12,529 people |
| Population Estimate | 12,336 |
Sources: Census ACS 5-Year 2023, Table B01003 · Refreshed 2026-04-12
Age Distribution
Median age 51.6y is 12.7 years older than the U.S. median (38.9y). Children under 18 make up 16% — below the U.S. share of ~22%.
| Age Summary · Median age | 51.6 years (vs Pennsylvania 41.2y) |
|---|---|
| Age Summary · Children Pct | 16.5% |
| Age Summary · Character | retirement community |
| Population under 18 | 2,070 |
| Median age | 51.6 years (vs Pennsylvania 41.2y) |
Sources: Census ACS 5-Year 2023 · Refreshed 2026-04-12
Race, Ethnicity & Diversity
Of 12,529 residents, race / ethnicity breaks down by Census ACS counts (a person can identify with one or more groups).
| White residents | 11,878 |
|---|---|
| Black residents | 218 |
| Asian residents | 35 |
| Hispanic or Latino residents | 202 |
| Diversity Index · Simpson Index | 10.0% |
| Diversity Index · Interpretation | less diverse |
| Asian population | 0.2% |
| Black population | 1.3% |
| Hispanic or Latino population | 1.6% |
| White (non-Hispanic) population | 93.8% |
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 (8)
Citizenship & Origin
Where residents were born and their citizenship status (Census ACS). 0.8% are foreign-born — below the U.S. average of 13.9%. 1% have naturalized to U.S. citizenship.
| Residents born in this state | 11,119 |
|---|---|
| Residents born in another state | 1,134 |
| Share born in this state | 88.7% |
| Share born in another state | 11.3% |
| Native-born U.S. citizens | 9.1% |
| Foreign-born residents | 0.8% |
| Naturalized citizens | 1.4% |
| Total foreign-born residents | 161 |
| From Europe | 65 |
| From Africa | 54 |
Households & Family Composition
5,692 households. Averaging 2.2 people each — smaller than the U.S. average of 2.5. 61% are family households — below the U.S. share of ~65%. Of 3,339 families, 14% are married couples with children.
| Children under 18 | 2,221 |
|---|---|
| Total families | 3,339 |
| Married couples with children | 471 |
| Single-parent households | 192 |
| Average household size | 2.17 |
| Women who gave birth (past year) | 14.4% |
| Grandparents living with grandchildren | 75 |
| Grandparents responsible for grandchildren | 18 |
| Family households | 3,461 households |
| Households that are families | 60.8% |
| Total households | 5,692 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. 9.9% moved within the county in the past year — the U.S. baseline is roughly 8–10%.
| Moved within the county (past year) | 9.9% |
|---|---|
| Migration · People moving in (annual) | 27,348 |
| Migration · People moving out (annual) | 27,368 |
| Migration · Net migration (in − out) | -20 |
| 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 | 1,148 |
|---|---|
| Disability rate | 9.2% |
Group Quarters
Group quarters are non-household living arrangements counted by the Census — college dormitories, nursing homes, military barracks, group homes, correctional facilities, and similar institutional or shared housing. 274 residents live in group quarters (2.2% of population).
| Living in group quarters | 274 |
|---|
Other
| Congressional District · District | 15 |
|---|---|
| Congressional District · Formatted | PA-15 |
| Congressional District · Congress | 118th |
| Cdc Birth Rate · Fips | 42,047 |
| Cdc Birth Rate · State Fips | 42 |
| Cdc Birth Rate · County Fips | 47 |
| Cdc Birth Rate · County | Elk |
| Cdc Birth Rate · Birth Rate | 15.8% |
| Cdc Birth Rate · Lower Ci | 12.30 |
| Cdc Birth Rate · Upper Ci | 20.00 |
| Cdc Mortality · Fips | 42,047 |
| Cdc Mortality · County | Elk County |
| Cdc Mortality · Urban Rural | Noncore |
| Cdc Mortality · Total Deaths 2020 2023 | 1,115 |
| Cdc Vaccination · Fips | 42,047 |
| Cdc Vaccination · County | Elk County |
| Cdc Vaccination · Dose1 Pop Pct | 63.9% |
| Cdc Vaccination · Series Complete Pct | 57.9% |
| Cdc Vaccination · Booster Pct | 51.7% |
| Cdc Vaccination · Population 2019 | 29,910 |
| Cdc Vaccination · Metro Status | Non-metro |
| Family Score · Score | 4.50 |
| Family Score · Schools | 7 |
| Family Score · Children Pct | 16.5% |
| Family Score · Rating | fair |
| Town Summary · Key Facts | population 12,529, stable, retirement community, middle-class, blue collar |
| Town Summary · Population | 12,529 people |
| Town Summary · County | Elk County |
Sources: Census place-to-CD118 crosswalk (place_fips) · federal dataset cascade