St. Marys: Demographics & People
8,301 people call St. Marys home, in 3,408 households. Population shrank 0.2% from 8,319 (2022) to 8,301 (2024). Median age 36.6 years. (4.4y younger than Auglaize County; 3.2y younger than Ohio). Children under 18 are 24% of the population. Population is 91% White (non-Hispanic) and 6% Hispanic or Latino. The community is relatively homogeneous (Simpson index 0.06). 64% of households are family-led. County is gaining 190 residents per year (2022-2023). County health: 43% adult obesity, 18% smoke.
- 2.4 people per household.
- 36% non-family households (singles, roommates).
Population & Trend
Population shrank 0.2% from 8,319 (2022) to 8,301 (2024). Estimated 2026 population: ~8,282 (extrapolated at -0.1%/yr trend). Census Bureau Vintage estimate: 8,258.
| Census data vintage | 2024 |
|---|---|
| Population | 46,422 people |
| Annual growth rate · Population change | -0.2% |
| Annual growth rate · Population (2022) | 8,319 |
| Annual growth rate · Population (2024) | 8,301 |
| Annual growth rate · Trend category | stable |
| Population | 8,301 people |
| Population Estimate | 8,258 |
Sources: Census ACS 5-Year 2023, Table B01003 · Refreshed 2026-04-12
Age Distribution
Median age 36.6y is 2.3 years younger than the U.S. median (38.9y). Children under 18 make up 24% — above the U.S. share of ~22%.
| Age Summary · Median age | 36.6 years (vs Ohio 39.8y) |
|---|---|
| Age Summary · Children Pct | 24.3% |
| Age Summary · Character | family-oriented |
| Population under 18 | 2,018 |
| Median age | 36.6 years (vs Ohio 39.8y) |
Sources: Census ACS 5-Year 2023 · Refreshed 2026-04-12
Race, Ethnicity & Diversity
Of 8,301 residents, race / ethnicity breaks down by Census ACS counts (a person can identify with one or more groups). The Simpson diversity index is 0.06 (0 = single group, 1 = perfectly even distribution); this is read as relatively homogeneous.
| White residents | 7,896 |
|---|---|
| Black residents | 117 |
| Asian residents | 43 |
| Hispanic or Latino residents | 72 |
| Diversity Index · Diversity index (Simpson) | 5.6% |
| Diversity Index · Diversity label | relatively homogeneous |
| Diversity Index · Groups counted | 4 |
| Diversity Index · Largest group share | 97.1% |
| Asian population | 0.1% |
| Black population | 1.7% |
| Hispanic or Latino population | 5.9% |
| White (non-Hispanic) population | 90.9% |
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). 0.3% are foreign-born — below the U.S. average of 13.9%. 0% have naturalized to U.S. citizenship.
| Residents born in this state | 7,220 |
|---|---|
| Residents born in another state | 1,044 |
| Share born in this state | 87.0% |
| Share born in another state | 13.0% |
| Native-born U.S. citizens | 12.6% |
| Foreign-born residents | 0.3% |
| Naturalized citizens | 0.1% |
| Total foreign-born residents | 82 |
| From Europe | 22 |
| From Africa | 60 |
Households & Family Composition
3,408 households. Averaging 2.4 people each — smaller than the U.S. average of 2.5. 64% are family households — near the U.S. share of ~65%. Of 2,174 families, 33% are married couples with children.
| Children under 18 | 1,926 |
|---|---|
| Total families | 2,174 |
| Married couples with children | 709 |
| Single-parent households | 124 |
| Average household size | 2.36 |
| Women who gave birth (past year) | 8.3% |
| Grandparents living with grandchildren | 112 |
| Grandparents responsible for grandchildren | 61 |
| Family households | 2,188 households |
| Households that are families | 64.2% |
| Total households | 3,408 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. 10.8% moved within the county in the past year — the U.S. baseline is roughly 8–10%. The surrounding county is gaining 190 residents per year on net (IRS migration data).
| Moved within the county (past year) | 10.8% |
|---|---|
| Migration · People moving in (annual) | 45,587 |
| Migration · People moving out (annual) | 45,397 |
| Migration · Net migration (in − out) | 190 |
| 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 | 505 |
|---|---|
| Disability rate | 6.1% |
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. 92 residents live in group quarters (1.1% of population).
| Living in group quarters | 92 |
|---|
Other
| Congressional District · District | 4 |
|---|---|
| Congressional District · Formatted | OH-04 |
| Congressional District · Congress | 118th |
| Cdc Birth Rate · Fips | 39,011 |
| Cdc Birth Rate · State Fips | 39 |
| Cdc Birth Rate · County Fips | 11 |
| Cdc Birth Rate · County | Auglaize |
| Cdc Birth Rate · Birth Rate | 19.1% |
| Cdc Birth Rate · Lower Ci | 15.90 |
| Cdc Birth Rate · Upper Ci | 22.70 |
| Cdc Mortality · Fips | 39,011 |
| Cdc Mortality · County | Auglaize County |
| Cdc Mortality · Urban Rural | Micropolitan |
| Cdc Mortality · Total Deaths 2020 2023 | 1,576 |
| Cdc Vaccination · Fips | 39,011 |
| Cdc Vaccination · County | Auglaize County |
| Cdc Vaccination · Dose1 Pop Pct | 42.0% |
| Cdc Vaccination · Series Complete Pct | 40.2% |
| Cdc Vaccination · Booster Pct | 53.3% |
| Cdc Vaccination · Population 2019 | 45,656 |
| Cdc Vaccination · Metro Status | Non-metro |
| Family Score · Score | 8.00 |
| Family Score · Schools | 14 |
| Family Score · Children Pct | 24.3% |
| Family Score · Rating | excellent |
| Town Summary · Key Facts | population 8,301, stable, family-oriented, upper-middle, mixed |
| Town Summary · Population | 8,301 people |
| Town Summary · County | Auglaize County |
Sources: Census place-to-CD118 crosswalk (place_fips) · federal dataset cascade