County Maps US

Marion County, Kentucky

A county in Kentucky, ranked 59 of 120 by population.

CountyFIPS 21155

Within Kentucky
Marion County, highlighted, with the areas around it. Boundaries generalised from the 2025 Census cartographic boundary file; neighbour fills carry no data. The dot marks Lebanon, the county seat, located via the 2025 Census Gazetteer.

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Population
20,115
+528 (+2.7%) since 2020
Land area
343.6
square miles. A further 1.0% of the total area is water
Population density
58.6
people per square mile, computed rather than published
County seat
Lebanon
Seat of county government.
Established
1834
191 years ago
Largest city
Lebanon city
Population 6,699.

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; Wikidata (CC0), Wikidata. Retrieved 30 August 2026.

Satellite view

Aerial imagery of Marion County with its boundary drawn on top. A map shows you the shape; this shows you what is inside it, and which side of the line a place falls on.

Aerial view of Marion County, Kentucky from the USGS National Map, with its boundary outlined
Imagery: USGS National Map, USGS Imagery Only, public domain, requested from USGS by your browser when you reach this point on the page, at 800 by 670 pixels. The boundary is the 2025 Census cartographic boundary file, reprojected to Web Mercator to match the imagery. You can also open the USGS National Map viewer.

Where Marion County ranks

Position among the 120 counties of Kentucky, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn KentuckyNationally
Population20,11559th of 1201,821st of 3,144
Land area343.6 sq mi50th of 1202,700th of 3,144
Population density58.6 per sq mi62nd of 1201,327th of 3,144
Median household income$59,62754th of 1202,113th of 3,143

Full data for Marion County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population20,115Vintage 2025 Population Estimates
Population in 202019,587Vintage 2025 Population Estimates
2020 estimates base?19,575Vintage 2025 Population Estimates
Land area343.6 sq mi2025 Gazetteer Files
Water area3.3 sq mi2025 Gazetteer Files
Total area346.9 sq mi2025 Gazetteer Files
Population density?58.6 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$59,627American Community Survey 2020-2024 5-Year Estimates
Median home value$168,100American Community Survey 2020-2024 5-Year Estimates
Median age40.4American Community Survey 2020-2024 5-Year Estimates
Households7,724American Community Survey 2020-2024 5-Year Estimates
Housing units8,477American Community Survey 2020-2024 5-Year Estimates

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; US Census Bureau, American Community Survey, American Community Survey 2020-2024 5-Year Estimates, released 29 January 2026. Population density is computed here, not published: it divides the Vintage 2025 population estimate by the 2025 Gazetteer land area, which are two different Census products. Retrieved 30 August 2026.

How the population changed

The Census Bureau publishes the components behind an estimate, not just the total. For the year to July 2025:

Births minus deaths
-3
224 births, 227 deaths
Net migration
+118
More people moved in than moved out.

Source: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026. Retrieved 30 August 2026.

The 6 areas bordering Marion County

Ordered by the length of the border actually shared, which the Census Bureau publishes in its county adjacency file and which no other county reference presents.

Bordering areaStateShared borderPopulation
Taylor CountyKentucky34 mi26,763
Washington CountyKentucky25 mi12,368
Nelson CountyKentucky14 mi49,036
Casey CountyKentucky11 mi16,205
Larue CountyKentucky8.0 mi15,184
Boyle CountyKentucky6.0 mi31,632

Source: US Census Bureau, County Adjacency File, 2025 County Adjacency File, released 15 September 2025. Retrieved 30 August 2026.

All 120 counties of Kentucky

Open the interactive Kentucky county map, or jump straight to any of them.

Data on this page last rebuilt 30 August 2026. How these figures are produced.