St. Mary's County, Maryland: Industrial Catholic Metro county. In 2024, voted R+17%. Democratic peak: D+36 in 1932.
Key facts
- 2024 presidential margin
- R+17MIT Election Lab
- Political typology
- Industrial Catholic MetroAkashic typology
- Population
- 115,1262024 5-year
- Median household income
- $119,4462024 5-year
- White (non-Hispanic)
- 71.3%2024 5-year
- Black
- 14.6%2024 5-year
- Hispanic / Latino
- 6.1%2024 5-year
- Peak Democratic margin
- D+36 in 1932MIT Election Lab
- Peak Republican margin
- R+36 in 1972MIT Election Lab
- Most similar
- Washington County, MD · similarity 0.99
2024 results by precinct
2024 precinct map of St. Mary's CountyPrecinct-level 2024 presidential results for St. Mary's County, with each precinct boundary colored by Democratic-vs-Republican margin.
—
Margin—
Turnout—
Harris +50Trump +50
Real precinct boundaries. Hover for vote totals.
presidential history
Presidential margin, 1876–2024
Democratic minus Republican, by election
| Year | Margin (D minus R) |
|---|---|
| 1876 | No data |
| 1880 | No data |
| 1884 | No data |
| 1888 | No data |
| 1892 | −4.5% |
| 1896 | −10.8% |
| 1900 | No data |
| 1904 | No data |
| 1908 | No data |
| 1912 | No data |
| 1916 | +14.5% |
| 1920 | −7.7% |
| 1924 | +8.0% |
| 1928 | +29.5% |
| 1932 | +36.3% |
| 1936 | +10.4% |
| 1940 | +10.7% |
| 1944 | −17.1% |
| 1948 | +1.0% |
| 1952 | −8.6% |
| 1956 | −11.5% |
| 1960 | +30.3% |
| 1964 | +33.9% |
| 1968 | −0.7% |
| 1972 | −36.2% |
| 1976 | +12.3% |
| 1980 | −9.3% |
| 1984 | −27.1% |
| 1988 | −26.3% |
| 1992 | −10.2% |
| 1996 | −7.8% |
| 2000 | −16.8% |
| 2004 | −26.2% |
| 2008 | −12.8% |
| 2012 | −14.8% |
| 2016 | −22.7% |
| 2020 | −13.8% |
| 2024 | −17.0% |
DemocraticRepublican
38 presidential elections
| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| R | 23,531 | 33,582 | 58,954 | ||
| R | 23,138 | 30,826 | 55,665 | ||
| R | 17,534 | 28,663 | 48,975 | ||
| R | 19,711 | 26,797 | 47,824 | ||
| R | 19,023 | 24,705 | 44,409 | ||
| R | 13,776 | 23,725 | 37,916 | ||
| R | 11,912 | 16,856 | 29,501 | ||
| R | 9,988 | 11,835 | 23,808 | ||
| R | 8,931 | 11,485 | 25,085 | ||
| R | 7,434 | 12,767 | 20,290 | ||
| R | 6,420 | 11,201 | 17,670 | ||
| R | 6,773 | 8,267 | 16,056 | ||
| D | 7,227 | 5,640 | 12,867 | ||
| R | 3,571 | 7,689 | 11,382 | ||
| R | 3,280 | 3,348 | 9,175 | ||
| D | 5,831 | 2,878 | 8,709 | ||
| D | 5,752 | 3,080 | 8,832 | ||
| R | 3,443 | 4,336 | 7,779 | ||
| R | 3,588 | 4,270 | 7,891 | ||
| D | 2,293 | 2,247 | 4,606 | ||
| R | 1,891 | 2,673 | 4,564 | ||
| D | 2,860 | 2,301 | 5,205 | ||
| D | 2,829 | 2,286 | 5,239 | ||
| D | 2,885 | 1,322 | 4,300 | ||
| D | 3,006 | 1,609 | 4,733 | ||
| D | 1,949 | 1,653 | 3,703 | ||
| R | 1,861 | 2,175 | 4,094 | ||
| D | 1,443 | 1,064 | 2,611 | ||
| — | 3,669 | 1,262 | 2,336 | ||
| — | 3,637 | 1,627 | 130 | ||
| — | 5,221 | 1,874 | 183 | ||
| — | 2,017 | 2,855 | 33 | ||
| R | 2,084 | 2,646 | 5,209 | ||
| R | 1,638 | 1,819 | 3,991 | ||
| — | — | — | — | ||
| — | — | — | — | ||
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Demographics
2024 ACS
Race, ethnicity, and ancestry
Click any group to see the ancestries typically reported within it.
German
15.4%
English
14.7%
Irish
12.8%
American
6.2%
Italian
5.1%
Scottish
2.1%
Polish
2.0%
African American
11.7%
Multiple ancestry combinations reported; no single grouping above 1%.
American Indian, Alaska Native, Native Hawaiian, and Pacific Islander combined.
Source · American Community Survey 5-year estimates, 2024 release. Hispanic/Latino is an ethnicity that overlaps the race categories, so these shares can total more than 100%. Ancestry is a self-reported, multiple-response item; ancestry percentages do not sum to the parent race percentage.
2024 ACS
Age distribution by sex
Median age: 37.2 in this county, 39.1 nationally
Male
Age
Female
85+
75–84
65–74
55–64
45–54
35–44
25–34
18–24
5–17
<5
Source · American Community Survey 5-year estimates, 2024 release.
2024 ACS
Median household income
Inflation-adjusted dollars
$119,446
St. Mary's County ranks in the top 0.5% of US counties.
St. Mary's County$119,446
Maryland$103,678
United States$80,734
St. Mary's County ranks in the top 0.5% of US counties by median household income.
Source · American Community Survey 5-year estimates, 2024 release.
2024 ACS
Poverty rate
All persons below federal poverty line
8.0%
Child poverty is below the national average.
Children under 188.7%
Working age (18–64)7.5%
Seniors (65+)11.5%
Source · American Community Survey 5-year estimates, 2024 release.
2024 ACS
Language at home
Population aged 5 and older
92.7%
speak English only
Spanish2.4%
Other Indo-European2.4%
Asian & Pacific Islander2.0%
Other languages0.5%
Source · ACS 5-year estimates, 2024.
2020 religion census
Religious adherents
Adherents per capita by tradition
Source · 2020 US Religion Census. Remaining 55.6% of residents not counted as adherents by any reporting body.
Home to one of the Navy's premier flight test centers, St. Mary's combines a substantial military and federal-contractor workforce with rural Southern Maryland demographics that have trended steadily Republican over the past two decades.
Its margins are typically close. The Democratic margin reached thirty-six points in 1932; the Republican margin reached thirty-six points in 1972. Between 2020 and 2024 the county moved three points toward the Republican candidate; the 2024 margin was seventeen points.
Its demographics sit near national norms: a 71% non-Hispanic-white share, a median household income of $119,446, and a 8% poverty rate. The county's voting pattern over the last decade is most similar to that of Washington County and Montour County.
Most similar counties
Compare two places, side by side
Twelve curated comparisons line up election history, demographics, and the divergence story for two places at a glance. Browse all comparisons →
Cite this page
All citations released under CC BY 4.0. Attribution: Akashic Intelligence.
St. Mary's County, Maryland. Akashic. https://akashic.app/county/24037/. Accessed May 20, 2026. License: CC BY 4.0.
License: CC BY 4.0
More in Maryland
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Frequently asked questions
How did St. Mary's County, Maryland vote in 2024?
In 2024, St. Mary's County, Maryland voted Republican by 17.0 points (R+17), carried by the Republican candidate. Out of 58,954 votes cast, 23,531 went Democratic and 33,582 went Republican.
What is St. Mary's County, Maryland's political typology?
Akashic places St. Mary's County, Maryland in the "Industrial Catholic Metro" typology — Mid-size industrial metros with Catholic ethnic roots — among the most competitive, swing-prone ground in the country. The typology is a data-driven cluster built from vote share, vote swing, race and ethnicity, income, language spoken at home, religion, and ancestry. Across 38 elections in the dataset, the county has voted Democratic 10 times, Republican 20 times, and other 0 times.
When did St. Mary's County, Maryland last vote Democratic?
The most recent presidential election in which St. Mary's County, Maryland voted Democratic was 1976.
How many people live in St. Mary's County, Maryland?
St. Mary's County, Maryland has a population of 115,126 according to the 2024 American Community Survey 5-year estimates from the US Census Bureau.
What is the median household income in St. Mary's County, Maryland?
Median household income in St. Mary's County, Maryland is $119,446 — above the national median of $80,734. The Maryland state median is $103,678.
What is the political history of St. Mary's County, Maryland?
Akashic tracks 38 presidential elections in St. Mary's County, Maryland from 1876 to 2024. Of those, 10 went Democratic and 20 went Republican. The county's typology — "Industrial Catholic Metro" — captures where that record, its demographics, and its recent swing place it among American communities.