St. Martinville: Demographics & People
Census counts 5,297 people in St. Martinville, in 2,848 households. Population shrank 1.3% from 5,367 (2022) to 5,297 (2024). Median age 49.4 years. (9.3y older than St. Martin Parish; 11.5y older than Louisiana). Children under 18 are 12% of the population. Population is 49% Black and 45% White (non-Hispanic). The community is moderately diverse (Simpson index 0.51). 53% of households are family-led. County is losing 68 residents per year (2022-2023). County health: 41% adult obesity, 21% smoke.
- 1.9 people per household.
- 47% non-family households (singles, roommates).
Population & Trend
Population shrank 1.3% from 5,367 (2022) to 5,297 (2024). Estimated 2026 population: ~5,228 (extrapolated at -0.7%/yr trend). Census Bureau Vintage estimate: 5,137.
| Census data vintage | 2024 |
|---|---|
| Population | 51,767 people |
| Annual growth rate · Population change | -1.3% |
| Annual growth rate · Population (2022) | 5,367 |
| Annual growth rate · Population (2024) | 5,297 |
| Annual growth rate · Trend category | declining |
| Population | 5,297 people |
| Population Estimate | 5,137 |
Sources: Census ACS 5-Year 2023, Table B01003 · Refreshed 2026-04-12
Age Distribution
Median age 49.4y is 10.5 years older than the U.S. median (38.9y). Children under 18 make up 12% — below the U.S. share of ~22%.
| Age Summary · Median age | 49.4 years (vs Louisiana 37.9y) |
|---|---|
| Age Summary · Children Pct | 11.7% |
| Age Summary · Character | established |
| Population under 18 | 621 |
| Median age | 49.4 years (vs Louisiana 37.9y) |
Sources: Census ACS 5-Year 2023 · Refreshed 2026-04-12
Race, Ethnicity & Diversity
Of 5,297 residents, race / ethnicity breaks down by Census ACS counts (a person can identify with one or more groups). The Simpson diversity index is 0.51 (0 = single group, 1 = perfectly even distribution); this is read as moderately diverse.
| White residents | 2,196 |
|---|---|
| Black residents | 2,920 |
| Asian residents | 16 |
| Hispanic or Latino residents | 66 |
| Diversity Index · Diversity index (Simpson) | 50.6% |
| Diversity Index · Diversity label | moderately diverse |
| Diversity Index · Groups counted | 4 |
| Diversity Index · Largest group share | 56.2% |
| Asian population | 0.4% |
| Black population | 48.9% |
| Hispanic or Latino population | 1.5% |
| White (non-Hispanic) population | 45.2% |
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). 1.6% are foreign-born — below the U.S. average of 13.9%. 1% have naturalized to U.S. citizenship.
| Residents born in this state | 4,785 |
|---|---|
| Residents born in another state | 360 |
| Share born in this state | 90.3% |
| Share born in another state | 9.7% |
| Native-born U.S. citizens | 6.8% |
| Foreign-born residents | 1.6% |
| Naturalized citizens | 1.3% |
| Total foreign-born residents | 61 |
| From Africa | 30 |
Households & Family Composition
2,848 households. Averaging 1.9 people each — smaller than the U.S. average of 2.5. 53% are family households — below the U.S. share of ~65%. Of 1,308 families, 13% are married couples with children.
| Children under 18 | 782 |
|---|---|
| Total families | 1,308 |
| Married couples with children | 174 |
| Single-parent households | 13 |
| Average household size | 1.93 |
| Women who gave birth (past year) | 16.0% |
| Grandparents living with grandchildren | 156 |
| Grandparents responsible for grandchildren | 54 |
| Family households | 1,505 households |
| Households that are families | 52.8% |
| Total households | 2,848 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. 6.9% moved within the county in the past year — the U.S. baseline is roughly 8–10%. The surrounding county is losing 68 residents per year on net (IRS migration data).
| Moved within the county (past year) | 6.9% |
|---|---|
| Migration · People moving in (annual) | 46,056 |
| Migration · People moving out (annual) | 46,124 |
| Migration · Net migration (in − out) | -68 |
| 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 | 671 |
|---|---|
| Disability rate | 12.5% |
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. 100 residents live in group quarters (1.9% of population).
| Living in group quarters | 100 |
|---|
Other
| Congressional District · District | 3 |
|---|---|
| Congressional District · Congress | 118th |
| Cdc Birth Rate · Fips | 22,099 |
| Cdc Birth Rate · State Fips | 22 |
| Cdc Birth Rate · County Fips | 99 |
| Cdc Birth Rate · County | St Martin |
| Cdc Birth Rate · Birth Rate | 31.2% |
| Cdc Birth Rate · Lower Ci | 27.10 |
| Cdc Birth Rate · Upper Ci | 35.60 |
| Cdc Mortality · Fips | 22,099 |
| Cdc Mortality · County | St. Martin Parish |
| Cdc Mortality · Urban Rural | Medium metro |
| Cdc Mortality · Total Deaths 2020 2023 | 1,320 |
| Cdc Vaccination · Fips | 22,099 |
| Cdc Vaccination · County | St. Martin Parish |
| Cdc Vaccination · Dose1 Pop Pct | 46.0% |
| Cdc Vaccination · Series Complete Pct | 41.3% |
| Cdc Vaccination · Booster Pct | 41.9% |
| Cdc Vaccination · Population 2019 | 53,431 |
| Cdc Vaccination · Metro Status | Metro |
| Family Score · Score | 4.60 |
| Family Score · Schools | 6 |
| Family Score · Childcare Centers | 2 |
| Family Score · Children Pct | 11.7% |
| Family Score · Rating | fair |
| Town Summary · Key Facts | population 5,297, declining, established, working-class, mixed |
| Town Summary · Population | 5,297 people |
| Town Summary · County | St. Martin Parish |
Sources: NCES school congressional district assignment · federal dataset cascade