St. Mary's County, Maryland Population 2024

115,779

St. Mary's County, Maryland's estimated 2024 population is 115,779 with a growth rate of 0.43% in the past year according to the most recent United States census data. St. Mary's County, Maryland is the 12th largest county in Maryland. The 2010 population was 105,772 and has seen a growth of 9.46% since that time.

Note: data after 2022 is projected based on recent change
Year
Population
Growth
Change
2029118,2694980.42%
2028117,7714980.42%
2027117,2734980.43%
2026116,7754980.43%
2025116,2774980.43%
2024115,7794980.43%
2023115,2814980.43%
2022114,7831330.12%
2021114,6506510.57%
2020113,9992350.21%
2019113,7648160.72%
2018112,9483210.29%
2017112,6277410.66%
2016111,8867940.71%
2015111,0921,0940.99%
2014109,9987140.65%
2013109,2844370.4%
2012108,8471,2581.17%
2011107,5891,8171.72%
2010105,77200%
199075,97416,07926.85%
198059,89512,50726.39%
197047,3888,47321.77%
196038,9159,80433.68%
195029,11114,48599.04%
194014,626-563-3.71%
193015,189-923-5.73%
192016,112-918-5.39%
191017,030-152-0.88%
190017,1821,3638.62%
189015,819-1,115-6.58%
188016,9341,99013.32%
187014,944-269-1.77%
186015,2131,51511.06%
185013,6984743.58%
184013,224-235-1.75%
183013,4594853.74%
182012,9741801.41%
181012,794-905-6.61%
180013,699-1,845-11.87%
179015,544-102,725-86.86%
2024 Growth Rate
0.43% (498)
County Website
St. Mary's County
County Seat
Leonardtown
2020 Population
113,999
Area
359 mi²
Density
323 people/mi²
Growth Since 2020
1.56% (1,780)
Founded
January 24, 1637

Population by Race

Race
Population
Percentage (of total)
White82,70272.31%
Black or African American16,87414.75%
Two or more races9,4538.27%
Asian2,9352.57%
Other race2,2902%
Native American1180.1%
Native Hawaiian or Pacific Islander00%

White

Black or African American

Two or more races

Asian

Other race

Native American

Native Hawaiian or Pacific Islander

St. Mary's County, Maryland Population by Race

St. Mary's County, Maryland Population Pyramid 2024

St. Mary's County, Maryland Median Age

37

Total

36.1

Male

37.9

Female

St. Mary's County, Maryland Adults

There are 86,873 adults, (15,711 of whom are seniors) in St. Mary's County, Maryland.

St. Mary's County, Maryland Age Dependency

60.7

Age Dependency Ratio

22.1

Old Age Dependency Ratio

38.6

Child Dependency Ratio

St. Mary's County, Maryland Sex Ratio

Female56,68949.57%
Male57,68350.43%

St. Mary's County, Maryland Population by Age

St. Mary's County, Maryland Renter vs Owner Occupied by Household Type

Household Type
Count
Average Size
Owner
Renter
All41,7432.6872.627.4
Married22,3813.298614
Non Family11,8901.2556.743.3
Female5,3283.1254.345.7
Male2,1443.1567.532.5

3.16

Average Family Size

2.68

Average Household Size

72.6%

Rate of Home Ownership

Married

Male

Female

NonFamily

owner

renter

St. Mary's County, Maryland Households and Families

Male

Female

Education Attained
Count
Percentage
9th to 12th Grade3,9285.12%
Associates Degree6,3418.26%
Bachelors Degree15,32519.96%
Graduate Degree11,62615.14%
High School Graduate21,99828.65%
Less Than 9th Grade1,9312.51%
Some College15,63420.36%

Less Than 9th Grade

9th to 12th Grade

High School Graduate

Some College

Associates Degree

Bachelors Degree

Graduate Degree

St. Mary's County, Maryland Educational Attainment by Sex (over 25)

St. Mary's County, Maryland Educational Attainment by Race

High School Graduation Rate

Bachelors Rate

Race
Total
High School
Bachelors
White56,61953,23821,403
Black11,0539,4152,069
2+ Races4,4974,3541,970
Hispanic3,7103,117959
Asian2,2762,1781,134
Other Race1,407927177
Native American61610

The highest rate of high school graduation is among native american people with a rate of 100%.

The highest rate of bachelors degrees is among asian people with a rate of 49.82%.

St. Mary's County, Maryland Educational Attainment by Race

All

Male

Female

Name
Average
Male
Female
Bachelors Degree$94,566$113,931$71,867
Graduate Degree$112,944$149,980$88,864
High School Graduate$49,282$65,077$38,819
Less Than 9th Grade$37,230$44,772$0
Overall$72,426$87,264$57,125
Some College$65,449$75,345$50,853

$72,426

Average Earnings

$87,264

Average Male

$57,125

Average Female

St. Mary's County, Maryland Earnings by Educational Attainment

St. Mary's County, Maryland Language by Age

Only English

Spanish

Other Indo-European Languages

Asian and Pacific Island Languages

Other Languages

St. Mary's County, Maryland Language

93.1% of St. Mary's County, Maryland residents speak only English, while 6.9% speak other languages. The non-English language spoken by the largest group is Spanish, which is spoken by 2.6% of the population.

St. Mary's County, Maryland Language

St. Mary's County, Maryland Poverty by Race

rate

Name
Total
In Poverty
Poverty Rate
White79,4614,5775.76%
Black16,4652,34914.27%
Multiple9,3287738.29%
Hispanic6,6734396.58%
Other2,27831914%
Asian2,8621515.28%

7.45%

Overall Poverty Rate

6.67%

Male Poverty Rate

8.24%

Female Poverty Rate

Poverty in St. Mary's County, Maryland

The race most likely to be in poverty in St. Mary's County, Maryland is Black, with 14.27% below the poverty level.

The race least likely to be in poverty in St. Mary's County, Maryland is Asian, with 5.28% below the poverty level.

The poverty rate among those that worked full-time for the past 12 months was 2.12%. Among those working part-time, it was 7.93%, and for those that did not work, the poverty rate was 16.29%.

St. Mary's County, Maryland Poverty

rate

Rate
Poverty
Less Than 9th Grade22.96%
High School9.32%
Some College6.51%
Bachelors or Greater1.78%

St. Mary's County, Maryland Poverty Rate by Education

rate

Rate
Poverty
Female Unemployed27.49%
Male Unemployed23.51%
Female Employed4.89%
Male Employed1.93%

St. Mary's County, Maryland Poverty Rate by Employment Status and Sex

St. Mary's County, Maryland Income by Household Type

Households

Families

MarriedFamilies

NonFamilies

Name
Median
Mean
Families$133,566$155,397
Households$114,580$138,624
Married Families$159,358$178,750
Non Families$75,133$88,217

mean

median

Income by Household Type

St. Mary's County, Maryland Marital Status

Married

Widowed

Divorced

Separated

NeverMarried

Marriage Rates

51.6%

Overall Marriage Rate

52.1%

Male Marriage Rate

51.2%

Female Marriage Rate

St. Mary's County, Maryland Married by Age and Sex

male

female

St. Mary's County, Maryland Marriage

The age group where males are most likely to be married is 55-64, while the female age group most likely to be married is 35-44.

St. Mary's County, Maryland Marital Status by Race

Married

Widowed

Divorced

Separated

NeverMarried

St. Mary's County, Maryland Marital Status

Second Gulf War

First Gulf War

Vietnam

Korea

World War II

11,871

Number of Veterans

10,292

Male Veterans

1,579

Female Veterans

War
Veterans
First Gulf War5,917
Second Gulf War5,220
Vietnam2,611
Korea229
World War II14

St. Mary's County, Maryland Veterans by War

count

Age Group
Veterans
35 to 544,524
55 to 643,144
65 to 741,730
75+1,396
18 to 341,077

St. Mary's County, Maryland Veterans by Age

count

Name
Veterans
% of Total
White9,08214.45%
Black1,41811.38%
2+ Races1,00319.73%
Hispanic81218.79%
Other Race25114.97%
Asian1174.97%

St. Mary's County, Maryland Veterans by Race

St. Mary's County, Maryland Veterans by Education

Less Than 9th Grade

High School Graduate

Some College

Bachelors or Greater

2.78%

Veteran Poverty Rate

20.44%

Veteran Disability Rate

St. Mary's County, Maryland Veterans by Education

LaborForceParticipation

68.3%

Labor Force Participation

63.1%

Employment Rate

3.8%

Unemployment Rate

St. Mary's County, Maryland Employment by Age

LaborForceParticipation

St. Mary's County, Maryland Employment by Race

LaborForceParticipation

St. Mary's County, Maryland Employment by Education

Origin of Non-Citizens

Europe

Asia

Africa

Oceania

Latin America

North America

Non citizens include legal permanent residents (green card holders), international students, temporary workers, humanitarian migrants, and illegal immigrants.

Origin of Naturalized Citizens

Europe

Asia

Africa

Oceania

Latin America

North America

48.76%

Born in St. Mary's County, Maryland

95.48%

Native Born

4.52%

Foreign Born

1.82%

Non Citizen

2.71%

Naturalized

Place of Birth

95.48% of St. Mary's County, Maryland residents were born in the United States, with 48.76% having been born in Maryland. 1.82% of residents are not US citizens. Of those not born in the United States, the largest percentage are from Asia.

St. Mary's County, Maryland Place of Birth

Sources