PA · GEOID 42043

Dauphin County area

Dauphin County, Pennsylvania covers 558.1 square miles: 524.9 square miles of land and 33.2 square miles of water.

Official Census measurements2026 Gazetteer · retrieved September 27, 2026
Land area524.9 mi²
Water area33.2 mi²
Total area558.1 mi²
National land rank#1994

County outline

Generalized outline of Dauphin County, Pennsylvania
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 Dauphin County is located

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

Area breakdown

Land accounts for 94% of Dauphin County’s measured area and water for 6%. Its combined area converts to 1,445.5 square kilometers or approximately 357,180 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land524.871,359.407335,916.8
Water33.22386.04721,262.7
Total558.0931,445.454357,179.5

How Dauphin County compares

By original Census land area, Dauphin County ranks #44 of 67 in Pennsylvania and #1994 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 0.803 times the Pennsylvania county-equivalent median of 653.3 square miles. It accounts for 1.2% of the combined county land area in the state.

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

What stands out about Dauphin County?

Dauphin County has more land than 1,228 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Dauphin County524.9 mi²
Pennsylvania median653.3 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 Dauphin County at #1,977 nationally by total area, 17 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 6%, compared with a national county-equivalent median of 1.2% — 4.8 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 Dauphin County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#1993Blair County, Pennsylvania525.1Compare
#1994Dauphin County, Pennsylvania524.9This county
#1995Mecklenburg County, North Carolina523.6Compare

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 40.411006, -76.799101. 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: 1,359,407,377 m²; AWATER: 86,047,350 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 Dauphin County?

The land measurement converts to approximately 335,917 acres. Including water, total area is approximately 357,180 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