County Maps US

Sullivan County, Missouri

A county in Missouri, ranked 106 of 115 by population.

CountyFIPS 29211

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

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Population
5,738
-247 (-4.1%) since 2020
Land area
648
square miles. A further 0.5% of the total area is water
Population density
8.9
people per square mile, computed rather than published
County seat
Milan
Seat of county government.
Established
1845
180 years ago
Largest city
Milan city
Population 1,742.

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 Sullivan 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 Sullivan County, Missouri 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 731 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 Sullivan County ranks

Position among the 115 counties of Missouri, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn MissouriNationally
Population5,738106th of 1152,755th of 3,144
Land area648 sq mi41st of 1151,456th of 3,144
Population density8.9 per sq mi109th of 1152,606th of 3,144
Median household income$56,96472nd of 1152,332nd of 3,143

Full data for Sullivan County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population5,738Vintage 2025 Population Estimates
Population in 20205,985Vintage 2025 Population Estimates
2020 estimates base?5,998Vintage 2025 Population Estimates
Land area648 sq mi2025 Gazetteer Files
Water area3.5 sq mi2025 Gazetteer Files
Total area651.5 sq mi2025 Gazetteer Files
Population density?8.9 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$56,964American Community Survey 2020-2024 5-Year Estimates
Median home value$115,600American Community Survey 2020-2024 5-Year Estimates
Median age44.1American Community Survey 2020-2024 5-Year Estimates
Households2,040American Community Survey 2020-2024 5-Year Estimates
Housing units3,010American 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
+1
78 births, 77 deaths
Net migration
-25
More people moved out than moved in.

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

The 5 areas bordering Sullivan 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
Putnam CountyMissouri30 mi4,546
Linn CountyMissouri27 mi11,815
Adair CountyMissouri21 mi25,684
Grundy CountyMissouri16 mi9,744
Mercer CountyMissouri8.1 mi3,404

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

All 115 counties of Missouri

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

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