Montana

Lewis and Clark

70,973
2020 population
1870
first census record
16
census records

About Lewis and Clark

Lewis and Clark, Montana, first appears in the United States federal census in 1870, when it recorded a population of 5,040. At the most recent census, in 2020, its population stood at 70,973.

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

On the ground today, one documented military engagement has been recorded within the county, among them Helena Saloon District Killings, MT, and 83 places are listed on the National Register of Historic Places.

Population by decade

Census YearPopulationChart
202070,973
201063,395
200055,716
199047,495
198043,039
197033,281
196028,006
195024,540
194022,131
193018,224
192018,660
191021,853
190019,171
189019,145
18806,521
18705,040
Source

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

Battles & engagements in Lewis and Clark

Military engagements that took place in Lewis and Clark, Montana.

Helena Saloon District Killings, MT
1874

Historic places in Lewis and Clark

National Register of Historic Places listings in Lewis and Clark, Montana.

Kluge House
Helena
Montana State Capitol Building
Helena
Helena Historic District (Boundary Increase II)
Helena
Dearborn River High Bridge
Augusta
Helena Historic District
Helena
Helena Historic District (Boundary Increase)
Helena
Evans, Christmas Gift, House
Helena
Alice Creek Historic District
Lincoln
Helena South-Central Historic District
Helena
Algeria Shrine Temple
Helena
Olsen House
Helena
Lewis and Clark County Hospital Historic District
Helena
Home of Peace
Helena
Fisk, Robert and Elizabeth, House
Helena
Temple Emanu-El
Helena
Benton Avenue Cemetery
Helena
Montana State Fairgrounds Racetrack
Helena
Cathedral of Saint Helena
Helena
Lincoln Lodge
Lincoln
Forestvale Cemetery
Helena
Power, C. B., Bungalow
Wolf Creek
Hauser Mansion
Helena
Former Montana Executive Mansion
Helena
Browse all Montanahistoric sites ›

Other counties in Montana

Explore census history and historic records for more Montana counties.

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Everything a full report reveals about Lewis and Clark County, Montana

This page charts the census history of Lewis and Clark County, Montana. 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 Lewis and Clark

When does Lewis and Clark first appear in the US census?
Lewis and Clark, Montana first appears in the federal census in 1870, with a recorded population of 5,040.
What is the population of Lewis and Clark?
At the most recent federal census (2020), Lewis and Clark had a recorded population of 70,973.
Were any battles fought in Lewis and Clark?
1 documented military engagement took place in Lewis and Clark, including Helena Saloon District Killings, MT.
How many historic places are in Lewis and Clark?
83 sites are listed on the National Register of Historic Places in Lewis and Clark, Montana.
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