St. Mary County, LA demographics:
population, income, and more

Total population
58,432
-1.3% year-over-year change
Median household income
$54,595/yr
-1.9% year-over-year change
Housing units
27,829
1.1% year-over-year change

St. Mary County population

How many people live in St. Mary County

St. Mary County is home to 58,432 residents, according to the most recent Census data. Gender-wise, 48.9% of St. Mary County locals are male, and 51.1% are female.

Total population
58,432
-1.3% year-over-year change
Gender ratio
Male
48.9%
28,592
Female
51.1%
29,840
Value Percent YoY change
Male 28,592 48.9% -1.5%
Female 29,840 51.1% -1.2%
A higher population often means more rental variety and livelier areas. The gender balance—how many men live here compared to women—can reveal a lot about the community and the lifestyles of its residents. Use this info to get a sense of the area's pace and personality.

Age demographics

The median age in St. Mary County is 39, with the population distributed as follows: about 20.5% are children under 15, then 12% are in the 15 to 24 age group. Adults between 25 and 44 make up 23.2% of the population, while another 25.9% fall into the 45 to 64 bracket. Finally, around 18.4% are 65 or older.

Median age
39.4
Age breakdown
Under 15
20.5%
15 to 24
12%
25 to 44
23.2%
45 to 64
25.9%
Over 65
18.4%
Value Percent YoY change
Under 15 11,988 20.5% -1.1%
15 to 24 6,988 12% -1.7%
25 to 44 13,585 23.2% -1.2%
45 to 64 15,119 25.9% -2.1%
Over 65 10,752 18.4% -0.5%
The age composition helps you get insight into who lives in the area. A younger population might mean a more active, fast-paced vibe, while an older one could suggest a quieter, slower lifestyle. If there's a balanced makeup, you’re likely to find a variety of services, housing types, and community spaces that cater to different life stages.

Racial makeup

In St. Mary County, 94.7% of the population are US-born citizens, while 2.4% have gained naturalized citizenship. At the same time, 2.9% of residents are non-citizens. As for race, 56.5% of locals are Caucasian, 29.9% are African American and 1.2% have Asian roots. There’s also a share of 7.9% that includes residents with two or more races.

Citizenship
U.S.-born citizens
94.7%
Non-U.S.-born citizens
2.4%
Non-citizens
2.9%
Value Percent YoY change
U.S.-born citizens 55,361 94.7% -1.9%
Non-U.S.-born citizens 1,399 2.4% 8.4%
Non-citizens 1,672 2.9% 12.7%
Racial breakdown
White
56.5%
Black or African American
29.9%
American Indian and Alaska Native
1.6%
Asian
1.2%
Native Hawaiian and other Pacific Islander
0%
Two or more races
7.9%
Other
2.9%
Value Percent
White 33,005 56.5%
Black or African American 17,445 29.9%
American Indian and Alaska Native 912 1.6%
Asian 731 1.2%
Native Hawaiian and other Pacific Islander 7 0%
Two or more races 4,621 7.9%
Other 1,711 2.9%

Households in St. Mary County

A peek inside St. Mary County households

St. Mary County has 22,733 households, with an average of 3 members in each. Of these, 65.4% are families, while the remaining 34.6% are made up of individuals living alone or with non-relatives, such as roommates.

Households stats

Total households
22,733
0.2% year-over-year change
Average people per household
3
Non-family households
7,872
Family households
14,861
Value Percent YoY change
Non-family households 7,872 34.6% 7.3%
Family households 14,861 65.4% -3.2%
The mix between family and non-family households gives a glimpse into daily life. A higher percentage of families might mean more parks and schools, while more non-family setups can mean flexible housing and diverse living styles. For renters, this can signal what kinds of homes are common and can help you figure out if the area matches your lifestyle.

Housing in St. Mary County

The housing landscape of St. Mary County

St. Mary County's housing consists of 27,829 units, with 70.1% being detached single-family homes ideal for those wanting space. Attached options, including duplexes and townhouses, make up 0.2% and offer a more compact, shared living style. Then there are the multifamily buildings in the area, and for those seeking flexibility, non-traditional options like mobile homes account for 18.6% of the housing landscape.

Housing units
27,829
1.1% year-over-year change
Housing types
Value Percent
1 unit, detached 19,497 70.1%
1 unit, attached 54 0.2%
2 units 981 3.5%
3 or 4 units 828 3%
5 to 9 units 656 2.4%
10 to 19 units 246 0.9%
20 to 49 units 298 1.1%
50 or more units 71 0.3%
Mobile home 5,166 18.6%
Boat, RV, van, etc. 32 0.1%
Homes built since 2020
140
40.0% year-over-year change

The age of buildings in St. Mary County

In St. Mary County, the median construction year is 1983. About 7.3% of homes were built before the 1940s, with another 4.5% going up by 1949. Most development happened in the second half of the 20th century. Then, 11.8% of homes were added from 2000 to 2009, 5% between 2010 and 2019, and 0.5% are part of the newest wave of development.

Construction year breakdown by decade
Value Percent YoY change
Built in 1939 or earlier 2,020 7.3% -3.9%
Built between 1940 and 1949 1,250 4.5% 9.5%
Built between 1950 and 1959 3,366 12.1% 4.1%
Built between 1960 and 1969 3,670 13.2% -7.0%
Built between 1970 and 1979 5,643 20.3% 8.6%
Built between 1980 and 1989 3,900 14% 14.4%
Built between 1990 and 1999 3,167 11.4% -8.4%
Built between 2000 and 2009 3,286 11.8% -5.5%
Built between 2010 and 2019 1,387 5% -5.0%
Built in 2020 or later 140 0.5% 40.0%
As a renter, knowing when homes were built helps you understand the potential condition and design of rental units. Newer builds may have more contemporary layouts, while older homes can offer character or larger lots, depending on the area.

St. Mary County occupancy rates

Out of the 22,733 occupied housing units in St. Mary County, 70.3% are owner-occupied, while 29.7% are lived in by tenants. Meanwhile, 18.3% of all homes on the local market sit vacant.

Occupied housing units
22,733
0.2% year-over-year change
Occupancy breakdown
Renter occupied
6,755
Owner occupied
15,978
Value Percent YoY
change
Renter occupied 6,755 29.7% 9.4%
Owner occupied 15,978 70.3% -3.3%
Unoccupied housing units
18.3%
Unoccupied housing units refer to homes that are currently without residents—whether they're waiting for renters or owners, used seasonally, or simply unclaimed. A higher share of empty homes may mean more housing availability, while a low number can reflect a tighter market with more competition. This, along with the renter-vs.-owner mix, helps paint a clearer picture of what types of housing and services are likely to be available in the area.

St. Mary County housing costs

Housing costs in St. Mary County come to a median of $798 per month, while tenants specifically pay a median gross rent of $861.

Median housing costs per month
$798/month
This figure sums up typical monthly housing costs for all households in the area. If you own, it includes mortgage payments in addition to property taxes, insurance and HOA fees. If you rent, it accounts for rent plus extras like utilities. It’s useful for seeing how local living expenses stack up compared to other places.
Median gross rent in St. Mary County
$861/month
Gross rent gives a more complete look at what renters actually pay, including not just base rent, but also utilities and fees. It’s a key number for evaluating rental affordability in your area of interest and understanding how it compares to nearby locations.

Education in St. Mary County

St. Mary County education at a glance

About 60.8% of the population in St. Mary County went to high school, while 14.5% pursued college studies. Another 6.1% earned an associate degree and 9.4% hold a bachelor’s. Meanwhile, 3.4% went even further, earning a master’s or doctorate.

Education level
Value Percent YoY change
No high school 2,570 5.8% -7.6%
High school diploma 26,828 60.8% 2.5%
College diploma 6,406 14.5% -11.3%
Associate degree 2,682 6.1% -12.3%
Bachelor's degree 4,124 9.4% 9.3%
Graduate degree 1,505 3.4% -9.6%
A community’s education mix can offer insights into the local economy and housing market. Higher levels of education often align with more job opportunities and stable incomes, which can increase demand for homes and influence both rent prices and rental availability.

Income in St. Mary County

How much people earn in St. Mary County

The average annual household income in St. Mary County was $68,803 in 2024, the most recent annual data available, according to the U.S. Census Bureau. This marked a +2.2% change from the previous year. At the same time, the median income stood at $54,595, reflecting a -1.9% shift over the same period.

Average household income in St. Mary County
$68,803/year
2.2% year-over-year change
Median household income in St. Mary County
$54,595/year
-1.9% year-over-year change

St. Mary County income by age

In St. Mary County, households led by residents aged 25 to 44 — usually in the early to mid stages of their careers — have a median income of $61,283. Those with someone between 45 and 64 in charge, often well established professionally, earn $68,456 overall. Younger households, where the main provider is under 25 and just starting out, report a median income of $38,470, while those led by someone over 65, many of whom may be retired, have about $42,387 in earnings. Overall, 78.6% of the locals in this community live above the poverty line.

Income breakdown by age
Value YoY change
Under 25 $38,470 -18.4%
25 - 44 $61,283 0.6%
45 - 64 $68,456 -3.9%
Over 65 $42,387 8.7%
Above poverty level
44,888
Below poverty level
12,246
Value Percent YoY
change
Above poverty level 44,888 78.6% -0.3%
Below poverty level 12,246 21.4% -5.6%

Employment in St. Mary County

Workforce and job types in St. Mary County

66.5% of the working population are employed in professional or administrative positions, while 33.5% are in hands-on or service-based jobs. Also, 11.3% run their own businesses, 70.9% are employed by private companies, and 13% work in the public sector.

Workforce demographics

White collar
15,533
Blue collar
7,810
Value Percent YoY change
White collar 15,533 66.5% -2.3%
Blue collar 7,810 33.5% 2.9%
Employer type
Self employees
11.3%
Private companies
70.9%
Governmental workers
13%
Not for profit companies
4.8%
Value Percent YoY change
Self employees 2,642 11.3% -0.9%
Private companies 16,547 70.9% -0.1%
Governmental workers 3,031 13% -4.9%
Not for profit companies 1,123 4.8% 5.2%

Transportation in St. Mary County

How people get around in St. Mary County

In St. Mary County, the average commute time is 76 minutes. Commuting methods vary: 97.8% of residents travel by personal vehicle and 1.7% prefer to walk, while the remaining share relies on public transit or on two wheelers to get from A to B.

Commute time
76 min
1.3% year-over-year change
Means of transportation
Value Percent YoY change
Car 20,792 97.8% -0.0%
Bicycle 95 0.4% -5.0%
Walk 366 1.7% 12.3%
Understanding how locals get to work can help you plan your own routine. High car usage might mean you’ll need a vehicle, while strong public transit or walkability could save you the hassle. Commute times also play a big role in quality of life—shorter trips can give you more time for the things you enjoy.

What is the median and average household income in St. Mary County by zipcode?

Zipcode Population Number of households Median income Average income
70514 1,914 787 $31,817 $48,883
70523 476 197 $63,408 $62,015
70342 4,607 1,712 $51,580 $75,634
70380 20,529 7,968 $54,595 $76,905
70392 8,173 3,056 $57,959 $72,669
70538 12,464 4,895 $52,407 $62,476
70544 10,269 4,118 $54,601 $83,038

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FAQs about St. Mary County demographics 

What is the total population of St. Mary County?

St. Mary County has a total population of 58,432 residents, according to the latest release from the U.S. Census Bureau: the 2019-2023 American Community Survey (ACS) 5-year estimates. This figure changed by -1.3% compared to a year ago.

What is the gender ratio in St. Mary County?

The gender ratio in St. Mary County is as follows:
  • 48.9% males (28,592 residents)
  • 51.1% females (29,840 residents)

What is the median age in St. Mary County?

The median age in St. Mary County is 39.4.

What is the age distribution of the population in St. Mary County?

The age distribution in St. Mary County is as follows:
  • Under 15: 20.5% (11,988 residents)
  • Ages 15-24: 12% (6,988 residents)
  • Ages 25-44: 23.2% (13,585 residents)
  • Ages 45-64: 25.9% (15,119 residents)
  • Over 65: 18.4% (10,752 residents)

What is the racial and ethnic makeup of St. Mary County?

The racial and ethnic makeup of St. Mary County is as follows:
  • White: 56.5% (33,005 residents)
  • Black or African American: 29.9% (17,445 residents)
  • American Indian and Alaska Native: 1.6% (912 residents)
  • Asian: 1.2% (731 residents)
  • Native Hawaiian and Other Pacific Islander: 0% (7 residents)
  • Two or More Races: 7.9% (4,621 residents)
  • Other: 2.9% (1,711 residents)

What percentage of the population in St. Mary County are U.S.-born citizens?

U.S.-born citizens represent 94.7% of the population in St. Mary County.

How many housing units are there in St. Mary County?

There are 27,829 housing units in St. Mary County, reflecting a +1.1% change compared to the previous year, according to the latest data from the U.S. Census Bureau.

How many households are in St. Mary County and what is the average household size?

St. Mary County has a total of 22,733 households, with an average of 3 people in each.

What is the median household income in St. Mary County?

St. Mary County has a median household income of $54,595, representing a -1.9% shift from the previous year, according to the U.S. Census Bureau.

What is the job market overview for St. Mary County?

Here’s a detailed breakdown of the local job market:

Job types:
  • White-collar workers: 66.5% (15,533 residents)
  • Blue-collar workers: 33.5% (7,810 residents)

Places of employment:
  • Self-employed: 11.3% (2,642 residents)
  • Private companies: 70.9% (16,547 residents)
  • Governmental workers: 13% (3,031 residents)
  • Not-for-profit companies: 4.8% (1,123 residents)

Data source & methodology

The demographic data on this page was sourced from the latest U.S. Census Bureau release—the 2019–2023 American Community Survey (ACS) 5-year estimates.

The information, issued annually, is compiled and published by the Point2Homes Research Team as soon as new data becomes available.

No representation, guarantee, or warranty is made concerning the accuracy or completeness of modified or aggregated information for particular areas.

Page last updated: September 2025