County Maps US

Grundy County, Missouri

A county in Missouri, ranked 88 of 115 by population.

CountyFIPS 29079

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

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Population
9,744
-20 (-0.2%) since 2020
Land area
435.3
square miles. A further 0.6% of the total area is water
Population density
22.4
people per square mile, computed rather than published
County seat
Trenton
Seat of county government.
Established
1841
184 years ago
Largest city
Trenton city
Population 5,557.

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 Grundy 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 Grundy 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 798 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 Grundy 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
Population9,74488th of 1152,430th of 3,144
Land area435.3 sq mi99th of 1152,329th of 3,144
Population density22.4 per sq mi72nd of 1152,148th of 3,144
Median household income$51,97593rd of 1152,659th of 3,143

Full data for Grundy County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population9,744Vintage 2025 Population Estimates
Population in 20209,764Vintage 2025 Population Estimates
2020 estimates base?9,815Vintage 2025 Population Estimates
Land area435.3 sq mi2025 Gazetteer Files
Water area2.7 sq mi2025 Gazetteer Files
Total area438 sq mi2025 Gazetteer Files
Population density?22.4 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$51,975American Community Survey 2020-2024 5-Year Estimates
Median home value$112,500American Community Survey 2020-2024 5-Year Estimates
Median age40.6American Community Survey 2020-2024 5-Year Estimates
Households3,907American Community Survey 2020-2024 5-Year Estimates
Housing units4,834American 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
-8
131 births, 139 deaths
Net migration
+3
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 Grundy 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
Livingston CountyMissouri21 mi14,708
Mercer CountyMissouri21 mi3,404
Sullivan CountyMissouri16 mi5,738
Daviess CountyMissouri12 mi8,558
Harrison CountyMissouri9.0 mi8,281
Linn CountyMissouri4.5 mi11,815

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.