66.4% of Pennsylvania Lives Within 100 Miles of Harrisburg. Mapped.

By SimpleMapLab·Published 13 May 2026·Rank #26 of 50 states·↑ All 50 states

66.4% of Pennsylvania’s population — about 8.64 M of 13.02 M residents — lives within 100 miles of Harrisburg. The other 33.6% — including Pittsburgh — sits beyond the circle.

A 100-mile geodesic radius around the Harrisburg, PA state capitol overlaid on Pennsylvania. 66.4% of Pennsylvania's population lives inside the dashed ring.

66.4%

of Pennsylvania’s population within 100 miles of Harrisburg

8.64 M

residents inside the radius (of 13.02 M statewide)

12 mi

from Harrisburg to Pennsylvania’s population centroid

#26

of 50 states ranked by capital-to-population centrality

Open this radius in the map → /tools/map-radius-tool · Harrisburg, PA · 100 mi
The link opens the SimpleMapLab Map Radius Tool with the 100-mile circle already drawn around the Harrisburg capitol. Change the radius to 50, 250, or any value to compare different framings.

Why this happened

Pennsylvania's capital is centrally located but not perfectly placed. Harrisburg's 100-mile circle captures roughly two-thirds to four-fifths of the state's residents — including Philadelphia (the largest city inside, ~1.52 million). The notable exception: Pittsburgh, sitting 162 miles from the capital. The capital itself sits 12 miles from Pennsylvania's population centroid — a moderate but not extreme offset.

The biggest cities inside the 100-mile radius

The top 5 most-populous places (by aggregated ZIP code population) sitting inside the 100-mile circle around Harrisburg. Cities are listed by total population captured by ZIP centroids in the dataset.

#	City	Population in radius
1	Philadelphia	1,515,992
2	Reading	228,034
3	York	187,437
4	Harrisburg	184,296
5	Allentown	179,222

The largest city outside the radius

Pennsylvania’s most-populous city outside the 100-mile circle is Pittsburgh, sitting 162 miles from Harrisburg. The aggregated population of Pittsburgh’s ZIP codes alone — 689,610 residents — illustrates the gap between Pennsylvania’s political seat and its population centre.

How Pennsylvania compares

The states ranked closest to Pennsylvania on this metric. Click any to compare the radius breakdown directly.

#25 Oklahoma

Oklahoma City · 67.5% pop. captured

#27 Indiana

Indianapolis · 62.4% pop. captured

#24 Wisconsin

Madison · 69.4% pop. captured

#28 West Virginia

Charleston · 61.6% pop. captured

#23 Kentucky

Frankfort · 70.1% pop. captured

Draw it yourself

Open the 100-mile circle around Harrisburg →

The Map Radius Tool lets you change the radius (try 50 mi for an urban-suburban question or 250 mi for “a day’s drive”), drag the centre to compare Harrisburg’s reach with that of Philadelphia, or add a second circle for a side-by-side comparison.

Methodology (brief)

We took the lat/lng of the Pennsylvania state capitol building (40.2732°, -76.8867°) and drew a 100-mile geodesic radius. For every ZIP code in Pennsylvania, we tested whether the ZIP centroid falls inside; if so, its population counts. We then divide by Pennsylvania’s total population to produce the percentage. The full methodology for all 50 states is on the hub page.

Suggested citation: SimpleMapLab (2026). 100 Miles Around Harrisburg: How Much of Pennsylvania Is Inside? Part of the State Capital Radius study. Retrieved from https://www.simplemaplab.com/studies/state-capital-radius/pennsylvania. Licensed under CC-BY 4.0.