IN · GEOID 18127

Porter County area

Porter County, Indiana covers 521.8 square miles: 418.1 square miles of land and 103.7 square miles of water.

Official Census measurements2026 Gazetteer · retrieved September 27, 2026
Land area418.1 mi²
Water area103.7 mi²
Total area521.8 mi²
National land rank#2423

County outline

Generalized outline of Porter County, Indiana
2025 Census cartographic boundary, fitted to this frame. County maps are not at a common scale. The 2026 area measurements below come from the separate Gazetteer release. Map source and limitations.

Where Porter County is located

Porter County highlighted on a map of all U.S. county equivalents. About the maps

Area breakdown

Land accounts for 80.1% of Porter County’s measured area and water for 19.9%. Its combined area converts to 1,351.5 square kilometers or approximately 333,970 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land418.1131,082.908267,592.3
Water103.715268.62166,377.6
Total521.8281,351.528333,969.9

How Porter County compares

By original Census land area, Porter County ranks #29 of 92 in Indiana and #2423 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 1.055 times the Indiana county-equivalent median of 396.4 square miles. It accounts for 1.2% of the combined county land area in the state.

See the complete Indiana ranking · What counts as a county equivalent?

What stands out about Porter County?

Porter County has more land than 799 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Porter County418.1 mi²
Indiana median396.4 mi²
National median604.5 mi²

A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.

Does including water change its rank?

Using land plus water places Porter County at #2,097 nationally by total area, 326 places closer to the top than its land rank. The water assigned to this geography moves it ahead of some county equivalents with more land.

Its water share is 19.9%, compared with a national county-equivalent median of 1.2% — 18.7 percentage points higher. This describes the statistical geography’s land/water mix, not flood exposure or developable land.

Closest positions in the national land ranking

These entries sit immediately beside Porter County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#2422Grundy County, Illinois418.1Compare
#2423Porter County, Indiana418.1This county
#2424Douglas County, Illinois416.7Compare

Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.

Representative coordinates

The Census internal point is 41.509506, -87.071506. It represents a location inside the geography; it is not necessarily the centroid or the address of a courthouse.

Source and precision

U.S. Census Bureau, 2026 Gazetteer Files, Counties. Original ALAND: 1,082,907,699 m²; AWATER: 268,619,698 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.

Download the official county source ZIP ↗ · Methodology

Common questions

How many acres of land are in Porter County?

The land measurement converts to approximately 267,592 acres. Including water, total area is approximately 333,970 acres. One square mile equals 640 acres.

Why might another source show a different area?

Check whether it reports land or total area, its Census vintage, and its rounding. Our guide explains how to reconcile county area figures.

Can this establish a property boundary?

No. Statistical measurements and generalized maps do not establish property lines. Consult the relevant local surveying or land-records authority.

Cite this county

Download the complete CSV or JSON dataset