| ZIP Codes: | 10 ZIP Codes (5 Standard, 5 PO Box, 0 Unique) [See All] |
| Area Codes: | 337 / 985 |
| Timezone: | Central (GMT -06:00) |
| Local Time: | 11:53:44 PM |
| Population: | 48,658 [See All] |
| FIPS: | 22101 |
| CBSA: | Morgan City, LA |
| Land Area: | 658 sq mi |
| Water Area: | 62 sq mi |
| Coordinates: | 29.7394, -91.3445 |
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48,658 residents live across 10 ZIPs covering 658 sq mi, served by 9 distinct USPS-recognized cities.
Population moved from 53,242 to 48,163 from 2014 to 2024 — a -9.5% change. 0 ZIPs gained residents, 7 lost.
The parish's wealthiest ZIP 70523 (Charenton, $63,408 median) and poorest ZIP 70522 (Centerville , $26,321) are 10.4 miles apart — a 2.4× income gap across local geography.
Median home values vary 1.8× across this parish — from $115,600 in 70514 (Baldwin) to $212,400 in 70342 (Berwick).
Density varies 2200× across the parish — from 32 people/sq mi in 70538 (Franklin) to 70,000 in 70523 (Charenton).
Educational attainment ranges from 4.8% bachelor's+ in 70514 (Baldwin) to 27.3% in 70342 (Berwick) — the breadth of educational profiles across the area.
Within Louisiana, this is the #22 most populous of 64 parishes and ranks #49 for median household income .
Weighted by population, the typical household earns about $53,217 across the parish — reflecting what a typical resident sees, not a simple ZIP average.
13.5% of adults age 25+ hold a bachelor's degree or higher (4,456 of 33,062 reporting).
5 Standard delivery, 5 PO Box only, 0 single-entity Unique ZIPs serve this parish.
A frontier parish — vast land area with only a few residents per square mile. Daily life looks very different here than in the country's denser counties.
Saint Mary Parish lost 8.6% of residents between 2014 and 2024. ZIPs that shed the largest share:
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 70380 | Morgan City | Standard | 20,529 | $54,595 | 140.4 | -9.1% |
| 70538 | Franklin | Standard | 12,464 | $52,407 | 391.6 | -13.4% |
| 70392 | Patterson | Standard | 8,173 | $57,959 | 92.3 | -3.8% |
| 70342 | Berwick | Standard | 4,607 | $51,580 | 29.3 | -6.9% |
| 70514 | Baldwin | Standard | 1,914 | $31,817 | 4.7 | -7.0% |
| 70522 | Centerville | PO Box | 495 | $26,321 | 0.0 | — |
| 70523 | Charenton | PO Box | 476 | $63,408 | 0.0 | -20.9% |
| 70340 | Amelia | PO Box | 0 | — | 0.0 | -100.0% |
| 70381 | Morgan City | PO Box | — | — | 0.0 | — |
| 70540 | Garden City | PO Box | — | — | 0.0 | — |