St. Martins: Demographics & People
St. Martins is home to 1,228 people, in 439 households. Population grew 2.8% from 1,195 (2022) to 1,228 (2024). Median age 38.1 years. (1.8y younger than Cole County; 1.1y younger than Missouri). Children under 18 are 28% of the population. Population is 90% White (non-Hispanic) and 3% Hispanic or Latino. The community is relatively homogeneous (Simpson index 0.05). 75% of households are family-led. County is gaining 414 residents per year (2022-2023). County health: 37% adult obesity, 16% smoke.
- 2.8 people per household.
- 25% non-family households (singles, roommates).
Population & Trend
Population grew 2.8% from 1,195 (2022) to 1,228 (2024) — about 4.6× the recent U.S. annual rate of ~0.6%/yr. Estimated 2026 population: ~1,262 (extrapolated at 1.4%/yr trend). Census Bureau Vintage estimate: 1,308.
| Census data vintage | 2024 |
|---|---|
| Population | 77,279 people |
| Annual growth rate · Population change | 2.8% |
| Annual growth rate · Population (2022) | 1,195 |
| Annual growth rate · Population (2024) | 1,228 |
| Annual growth rate · Population growing | Yes |
| Annual growth rate · Trend category | growing |
| Population | 1,228 people |
| Population Estimate | 1,308 |
Sources: Census ACS 5-Year 2023, Table B01003 · Refreshed 2026-04-12
Age Distribution
Median age 38.1y is 0.8 years younger than the U.S. median (38.9y). Children under 18 make up 28% — above the U.S. share of ~22%.
| Age Summary · Median age | 38.1 years (vs Missouri 39.2y) |
|---|---|
| Age Summary · Children Pct | 27.6% |
| Age Summary · Character | family-oriented |
| Population under 18 | 339 |
| Median age | 38.1 years (vs Missouri 39.2y) |
Sources: Census ACS 5-Year 2023 · Refreshed 2026-04-12
Race, Ethnicity & Diversity
Of 1,228 residents, race / ethnicity breaks down by Census ACS counts (a person can identify with one or more groups). The Simpson diversity index is 0.05 (0 = single group, 1 = perfectly even distribution); this is read as relatively homogeneous.
| White residents | 1,116 |
|---|---|
| Black residents | 2 |
| Hispanic or Latino residents | 28 |
| Diversity Index · Diversity index (Simpson) | 5.1% |
| Diversity Index · Diversity label | relatively homogeneous |
| Diversity Index · Groups counted | 3 |
| Diversity Index · Largest group share | 97.4% |
| Asian population | 0.7% |
| Black population | 0.1% |
| Hispanic or Latino population | 2.9% |
| White (non-Hispanic) population | 90.1% |
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 (8)
Citizenship & Origin
Where residents were born and their citizenship status (Census ACS). 0.2% are foreign-born — below the U.S. average of 13.9%. 1% have naturalized to U.S. citizenship.
| Residents born in this state | 966 |
|---|---|
| Residents born in another state | 248 |
| Share born in this state | 78.7% |
| Share born in another state | 21.3% |
| Native-born U.S. citizens | 20.2% |
| Foreign-born residents | 0.2% |
| Naturalized citizens | 0.9% |
| Total foreign-born residents | 2,236 |
Households & Family Composition
439 households. Averaging 2.7 people each — larger than the U.S. average of 2.5. 75% are family households — above the U.S. share of ~65%. Of 325 families, 32% are married couples with children.
| Children under 18 | 320 |
|---|---|
| Total families | 325 |
| Married couples with children | 103 |
| Single-parent households | 7 |
| Average household size | 2.70 |
| Women who gave birth (past year) | 10.8% |
| Grandparents living with grandchildren | 35 |
| Family households | 331 households |
| Households that are families | 75.4% |
| Total households | 439 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. 7.5% moved within the county in the past year — the U.S. baseline is roughly 8–10%. The surrounding county is gaining 414 residents per year on net (IRS migration data).
| Moved within the county (past year) | 7.5% |
|---|---|
| Migration · People moving in (annual) | 72,796 |
| Migration · People moving out (annual) | 72,382 |
| Migration · Net migration (in − out) | 414 |
| 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 | 95 |
|---|---|
| Disability rate | 7.9% |
Other
| Congressional District · District | 3 |
|---|---|
| Congressional District · Formatted | MO-03 |
| Congressional District · Congress | 118th |
| Cdc Birth Rate · Fips | 29,051 |
| Cdc Birth Rate · State Fips | 29 |
| Cdc Birth Rate · County Fips | 51 |
| Cdc Birth Rate · County | Cole |
| Cdc Birth Rate · Birth Rate | 17.6% |
| Cdc Birth Rate · Lower Ci | 15.20 |
| Cdc Birth Rate · Upper Ci | 20.30 |
| Cdc Mortality · Fips | 29,051 |
| Cdc Mortality · County | Cole County |
| Cdc Mortality · Urban Rural | Small metro |
| Cdc Mortality · Total Deaths 2020 2023 | 3,552 |
| Cdc Vaccination · Fips | 29,051 |
| Cdc Vaccination · County | Cole County |
| Cdc Vaccination · Dose1 Pop Pct | 62.5% |
| Cdc Vaccination · Series Complete Pct | 55.0% |
| Cdc Vaccination · Booster Pct | 47.5% |
| Cdc Vaccination · Population 2019 | 76,745 |
| Cdc Vaccination · Metro Status | Metro |
| Family Score · Score | 3.50 |
| Family Score · Schools | 5 |
| Family Score · Children Pct | 27.6% |
| Family Score · Rating | fair |
| Town Summary · Key Facts | population 1,228, growing, family-oriented, upper-middle, white collar |
| Town Summary · Population | 1,228 people |
| Town Summary · County | Cole County |
Sources: Census place-to-CD118 crosswalk (place_fips) · federal dataset cascade