Maryland

St. Mary's

113,777
2020 population
1790
first census record
24
census records

About St. Mary's

St. Mary's, Maryland, first appears in the United States federal census in 1790, when it recorded a population of 15,544. At the most recent census, in 2020, its population stood at 113,777.

The county's recorded population has risen across the decades to its highest level in 2020.

On the ground today, 10 documented military engagements have been recorded within the county, among them Ingle's Rebellion, Ingle's Rebellion 1645, Ingle's Rebellion – Plundering of St. Mary's 1645, and 32 places are listed on the National Register of Historic Places.

Population by decade

Census YearPopulationChart
2020113,777
2010105,151
200086,211
199075,974
198059,895
197047,388
196038,915
195029,111
194014,626
193015,189
192016,112
191017,030
190017,182
189015,819
188016,934
187014,944
186015,213
185013,698
184013,224
183013,459
182012,974
181012,794
180013,699
179015,544
Source

Population data from the United States decennial census, U.S. Census Bureau (public domain).

Battles & engagements in St. Mary's

Military engagements that took place in St. Mary's, Maryland.

Ingle's Rebellion
1644
Ingle's Rebellion 1645
1645
Ingle's Rebellion – Plundering of St. Mary's 1645
1645
Ingle's Plundering of St. Mary's City 1645
1645
Raid on St. Mary's County (1776)
1776
Raid on Leonardtown and St. Mary's County
1814
Raid on Leonardtown and St. Mary's County (1814)
1814
Action at Leonard's Creek MD
1814
Skirmish at Cedar Point MD
1814
Point Lookout Prison Camp Operations
1863

Historic places in St. Mary's

National Register of Historic Places listings in St. Mary's, Maryland.

Mattapany-Sewall Archeological Site
Lexington Park
Deep Falls
Chaptico
St. Marys City Historic District
St. Marys City
Sotterley
Hollywood
St. Clement's Island Historic District
Colton
Porto Bello
Drayden
Bard's Field
Ridge
U-1105 BLACK Panther (Type VIIC German Submarine)
Piney Point
Mulberry Fields
Beauvue
De La Brooke Tobacco Barn
Oraville
Ocean Hall
Bushwood
River View, The
Oakley
St. Francis Xavier Church and Newtown Manor House
Compton
St. Andrew's Church
Leonardtown
St. Ignatius Roman Catholic Church
St. Inigoes
St. George's Protestant Episcopal Church
Valley Lee
Woodlawn
St. Marys
Bachelor's Hope
Chaptico
Cecil's Mill Historic District
Great Mills
Abell house
Leonardtown
All Faith Church
Charlotte Hall
St. Richard's Manor
Lexington Park
Cross Manor
St. Inigoes
Christ Episcopal Church
Chaptico
Browse all Marylandhistoric sites ›

Other counties in Maryland

Explore census history and historic records for more Maryland counties.

AlleganyAnne ArundelBaltimoreBaltimore cityCalvertCarolineCarrollCecilCharlesDorchesterFrederickGarrettHarfordHowardKentMontgomeryPrince George'sQueen Anne'sSomersetTalbot
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Everything a full report reveals about St. Mary's County, Maryland

This page charts the census history of St. Mary's County, Maryland. A full Aubrey report for an address here pulls together everything the historical record holds about the ground, from the earliest settlement to the twentieth century:

Overview
An interactive map of the location with historic sites, battles and Native heritage plotted, and its full story era by era.
The Land
The historic sites and place names around the location, and how this land was settled and used.
Geology
The bedrock beneath the site, its age and rock type, reaching back millions of years.
LiDAR Terrain
Laser-scanned terrain that reveals earthworks and old features hidden in the landscape.
Conflict & War
The battles, raids and skirmishes fought near here, across every era of American conflict.
The Civil War
The Civil War on this ground, 1861 to 1865: who held it, and the battles, camps and regiments nearby.
The Soldiers
The men who marched from here in the Civil War, named and traced where the record allows.
Native Heritage
The Native nations who held this land, mapped across time from before European contact to today.
Settlement
Who claimed and held this ground, from Indigenous homelands through the colonial powers to the United States.
The Community
How the town grew, who came, and what kind of place it became, traced through the census record.
Rivers & Rail
The rivers, canals and railroads that connected this place between 1830 and 1911.
Notable People
The people born, buried or genuinely tied to this exact place, with their stories.
Historical Maps
Historic maps of the location layered over how it looks today.
Finds & Access
Museum objects tied to the area, and the laws on searching, collecting and access here.
Literature
The old books, county histories and archives that mention this place, quoted with their sources.
Spotlight
A deep dive into the most remarkable, lesser-known history of the place, traced back to the record.
Points of Interest
The most significant historic sites and landmarks near the location, and why they matter.
Timeline
The whole story of the location told era by era, from first peoples to the present day.
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Frequently asked about St. Mary's

When does St. Mary's first appear in the US census?
St. Mary's, Maryland first appears in the federal census in 1790, with a recorded population of 15,544.
What is the population of St. Mary's?
At the most recent federal census (2020), St. Mary's had a recorded population of 113,777.
Were any battles fought in St. Mary's?
10 documented military engagements took place in St. Mary's, including Ingle's Rebellion, Ingle's Rebellion 1645, Ingle's Rebellion – Plundering of St. Mary's 1645.
How many historic places are in St. Mary's?
32 sites are listed on the National Register of Historic Places in St. Mary's, Maryland.
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