St. Mary Parish, Louisiana Demographics
Population trends, housing costs, income, commuting, and health, all on one page.
St. Mary Parish, LA Population Density Map and Area Scores
Area Score
Health, income and education, each graded from F to A+. Explore interactive maps for deeper analysis.
-
C
Health Below average
-
D
Income Well below average
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F
Education Well below averageLess educated than 90% of counties in Louisiana
Source: Map AI Methodology
Population: density and quick facts
| Metric | St. Mary Parish | Louisiana Avg | U.S. Average |
|---|---|---|---|
| Population | 47,828 | 4,610,276 | 337,468,954 |
| Population density (per sq mi) | 42.7 | 88.0 | 86.4 |
| Population growth (%/yr) | -1.29% | -0.10% | 0.59% |
| Median age | 38.4 | 35.9 | 37.3 |
| Households | 18,463 | 1,803,262 | 130,235,071 |
Population in St. Mary Parish declined by 6.4% from 2009 to 2024, reaching 47,828 in 2024.
Population Growth 2009–2024
Race & Ethnicity
Age & Sex
The largest generation in St. Mary Parish is Gen X, aged 45–60, at 21.1% of residents. That is 1.7 points above Louisiana as a whole.
- Gen Z 13–28 9,829 20.6% -0.9 pts
- Millennials 29–44 9,273 19.4% -2.5 pts
- Gen X 45–60 10,071 21.1% +1.7 pts
- Boomers 61–79 8,549 17.9% +0.7 pts
Residents by birth cohort, from the 2025 age distribution. The right-hand figure is how far each cohort's share sits above or below Louisiana, in percentage points. Children younger than Gen Z and the generations before the Boomers are counted in the population but not shown here, so these shares do not add up to 100%.
Male and female share
Women are 50.9% of the people living in St. Mary Parish and men 49.1%.
- Women 50.9% Louisiana 51.1%
- Men 49.1% Louisiana 48.9%
How many residents match a customer profile?
Residents matching this profile
100% of everyone living in St. Mary Parish
Pick an age range and a women/men split and the figure above answers with how many residents that profile reaches.
Economy
St. Mary Parish has a the economy index of D, which means it is barely prosperous.
| Metric | St. Mary Parish | Louisiana Avg | U.S. Average |
|---|---|---|---|
| Median household income | $53,303 | $60,934 | $80,455 |
| Income growth (%/yr) | 3.44% | 3.69% | 4.80% |
| Unemployment rate | 5.4% | 6.2% | 5.2% |
The median household income in St. Mary Parish is about 13% lower than in Louisiana.
Housing
| Metric | St. Mary Parish | Louisiana Avg | U.S. Average |
|---|---|---|---|
| Median home price | $213,709 | $170,446 | $248,835 |
| Median rent | $847 | $1,063 | $1,407 |
| Homeownership rate | 68.6% | 67.4% | 65.2% |
The median home price in St. Mary Parish is about 21.0 years' worth of rent — buying at the median price costs roughly as much as paying the median rent of $847 per month for that long.
Commute Time & Mobility
Commuters in St. Mary Parish spend about 31 minutes on the road round trip each working day. Over a typical 250-day work year, that adds up to roughly 129 hours, about 5.4 full days, spent commuting.
| Metric | St. Mary Parish | Louisiana Avg | U.S. Average |
|---|---|---|---|
| One-way commute (min) | 15.5 | 21.3 | 22.4 |
| Round-trip commute (min) | 31.0 | 42.5 | 44.8 |
| Yearly time spent (hours) | 129 | 177 | 187 |
| Estimated yearly cost | $4,000 | $5,493 | $5,790 |
| Work from home | 5.5% | 8.1% | 15.0% |
| Highway traffic (vehicles/day) | 5,986 | 8,275 | 8,813 |
| Local road traffic (vehicles/day) | 771 | 1,164 | 1,355 |
Fastest commutes among counties in
Louisiana:
East Carroll Parish (11.4 min), Madison Parish (13.1 min), St. Mary Parish (15.5 min).
Slowest:
West Feliciana Parish (32.8 min), East Feliciana Parish (32.8 min), St. Helena Parish (32.4 min).
The average commute time in St. Mary Parish is 15 minutes, shorter than the 21 minutes in Louisiana.
Estimated yearly cost applies a single national wage rule of thumb (U.S. Bureau of Labor Statistics average hourly earnings), not a measurement of wages in this area. Traffic volume figures come from proprietary Ticon and TrafficZoom data.
Education & Households
St. Mary Parish has a education index of F, which means it scores poorly in education.
| Metric | St. Mary Parish | Louisiana Avg | U.S. Average |
|---|---|---|---|
| Bachelor's degree or higher | 11.6% | 24.0% | 31.6% |
| Average household size | 2.55 | 2.49 | 2.53 |
Highest education index among counties in
Louisiana:
Orleans Parish (0.3), East Baton Rouge Parish (0.3), St. Tammany Parish (0.3).
Lowest:
East Carroll Parish (0.1), Assumption Parish (0.2), Evangeline Parish (0.2).
Health
St. Mary Parish has a health index of C, which means it is somewhat healthy.
| Metric | St. Mary Parish | Louisiana Avg | U.S. Average |
|---|---|---|---|
| Life expectancy (years) | 74.0 | 75.1 | 78.3 |
| Self-rated poor health | 23.0% | 22.3% | 16.3% |
| Smokers | 23.5% | 23.9% | 19.0% |
Highest health index among counties in
Louisiana:
St. Tammany Parish (0.8), Ascension Parish (0.8), Vernon Parish (0.8).
Lowest:
East Carroll Parish (0.7), Madison Parish (0.7), Tensas Parish (0.7).
St. Mary Parish, LA Compared With Nearby Counties
St. Mary Parish, LA is typical in size for this group, 47,828 residents against a local median of 51,353, so the measures below are close to a like for like comparison. Where St. Mary Parish, LA breaks from the counties next to it is median home price, sitting 55% above the local median of $137,826 at $213,709.
Commute tells the same story from another angle: 15.5 min against a local median of 20.6 min, 25% below it. The one measure here that carries a verdict is commute, and at 25% below the local median it puts St. Mary Parish, LA at the better end of the local range. The counties themselves spread $129,874 on median home price, so St. Mary Parish, LA sits at one end of an already wide local range rather than apart from it. St. Mary Parish, LA has the highest median home price of the 6 areas compared here.
| Area | Population | Median household income | Median home price | Commute |
|---|---|---|---|---|
| St. Mary Parish, LA | 47,828 | $53,303 #5/6 | $213,709 #1/6 | 15.5 min #1/6 |
| Iberia Parish, LA | 68,630 | $56,492 | $154,658 | 20.6 min |
| Assumption Parish, LA | 20,480 | $52,234 | $116,945 | 27.2 min |
| St. Martin Parish, LA | 51,353 | $56,973 | $72,210 | 23.5 min |
| Iberville Parish, LA | 29,819 | $55,441 | $137,826 | 18.1 min |
| Terrebonne Parish, LA | 106,185 | $64,594 | $202,083 | 18.4 min |
Frequently Asked Questions
Common questions about St. Mary Parish, Louisiana.
How big is St. Mary Parish, Louisiana by population?
About 47,828 people live in St. Mary Parish, Louisiana, in 18,463 households of 2.6 people on average. The median age is 38.4, close to the U.S. median of 37.3.
How densely populated is St. Mary Parish, Louisiana?
Averaged over its land area, St. Mary Parish, Louisiana has 43 people per square mile, a density typical of rural areas. That is about 49% of the U.S. average of 86.
Can a typical household afford a home in St. Mary Parish, Louisiana?
The median home costs 4.0 times the median household income ($213,709 against $53,303), compared with 3.1 times nationally. A ratio of about 3 is traditionally considered affordable. Median rent of $847 a month takes about 19% of the median household's income, below the 30% level at which HUD considers renters cost-burdened.
How common is a college degree in St. Mary Parish, Louisiana?
11.6% of adults in St. Mary Parish, Louisiana hold a bachelor's degree or higher (about 1 in 9), well below the U.S. share of 31.6%.
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