County Maps US

Hamilton County, Iowa

A county in Iowa, ranked 49 of 99 by population.

CountyFIPS 19079

Within Iowa
Hamilton County, highlighted, with the areas around it. Boundaries generalised from the 2025 Census cartographic boundary file; neighbour fills carry no data.

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Population
14,944
-70 (-0.5%) since 2020
Land area
576.7
square miles. A further 0.1% of the total area is water
Population density
25.9
people per square mile, computed rather than published
County seat
Webster City
Seat of county government.
Established
1856
169 years ago
Largest city
Webster City city
Population 7,815.

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 Hamilton 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 Hamilton County, Iowa 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 749 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 Hamilton County ranks

Position among the 99 counties of Iowa, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn IowaNationally
Population14,94449th of 992,100th of 3,144
Land area576.7 sq mi36th of 991,716th of 3,144
Population density25.9 per sq mi50th of 992,042nd of 3,144
Median household income$72,43241st of 991,018th of 3,143

Full data for Hamilton County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population14,944Vintage 2025 Population Estimates
Population in 202015,014Vintage 2025 Population Estimates
2020 estimates base?15,040Vintage 2025 Population Estimates
Land area576.7 sq mi2025 Gazetteer Files
Water area0.76 sq mi2025 Gazetteer Files
Total area577.5 sq mi2025 Gazetteer Files
Population density?25.9 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$72,432American Community Survey 2020-2024 5-Year Estimates
Median home value$156,400American Community Survey 2020-2024 5-Year Estimates
Median age41.7American Community Survey 2020-2024 5-Year Estimates
Households6,434American Community Survey 2020-2024 5-Year Estimates
Housing units7,040American 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
+23
207 births, 184 deaths
Net migration
-77
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 6 areas bordering Hamilton 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
Webster CountyIowa26 mi36,838
Hardin CountyIowa26 mi16,455
Wright CountyIowa24 mi12,801
Story CountyIowa12 mi101,291
Boone CountyIowa12 mi26,799
Franklin CountyIowaa single point9,868

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

All 99 counties of Iowa

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

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