County outline
Where Franklin County is located
Area breakdown
Land accounts for 99.9% of Franklin County’s measured area and water for 0.1%. Its combined area converts to 2,001.7 square kilometers or approximately 494,643 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 772.279 | 2,000.193 | 494,258.6 |
| Water | 0.6 | 1.554 | 384 |
| Total | 772.879 | 2,001.747 | 494,642.6 |
How Franklin County compares
By original Census land area, Franklin County ranks #27 of 67 in Pennsylvania and #1125 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 1.182 times the Pennsylvania county-equivalent median of 653.3 square miles. It accounts for 1.7% of the combined county land area in the state.
See the complete Pennsylvania ranking · What counts as a county equivalent?
Population and density of Franklin County
The Census Bureau estimates that 160,652 people lived in Franklin County on July 1, 2025. That ranks #437 of 3,222 county equivalents nationally and #22 of 67 in Pennsylvania. Since the April 1, 2020 estimates base of 155,944, the population has grown by 4,708 (+3%), compared with +0.4% for Pennsylvania as a whole.
With 772.3 square miles of land, that is 208 people per square mile (80 per km²), placing Franklin County #629 nationally for density and #25 in Pennsylvania. The median county equivalent has 47 people per square mile; the Pennsylvania median is 137. Put another way, there are about 3.1 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 155,938 | 156,597 | 157,038 | 158,181 | 159,476 | 160,652 |
| Change | — | +659 | +441 | +1,143 | +1,295 | +1,176 |
U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.
Cities and towns in Franklin County
Franklin County is divided into 22 municipalities and townships. In Pennsylvania, county subdivisions are local governments, and together they cover all of the county’s land and residents.
The most populous is Chambersburg borough, with 23,376 residents (14.6% of the county). The largest by land is Letterkenny township, at 70.4 mi², or 9.1% of the county’s land. Among those with at least 1,000 residents in 2020, Chambersburg borough grew fastest since then (+6.7%).
| County subdivision | Population 2025 | Since 2020 | Land mi² | Share of county land |
|---|---|---|---|---|
| Chambersburg boroughCounty seat | 23,376 | +6.7% | 6.93 | 0.9% |
| Greene township | 18,721 | +1.6% | 57.3 | 7.4% |
| Antrim township | 16,481 | +4.3% | 70.1 | 9.1% |
| Washington township | 15,518 | +4.5% | 39.1 | 5.1% |
| Guilford township | 15,371 | +5% | 51.2 | 6.6% |
| Hamilton township | 11,759 | +3.3% | 35.5 | 4.6% |
| Waynesboro borough | 11,190 | +1.5% | 3.431 | 0.4% |
| Southampton township | 8,604 | +0.5% | 38.2 | 5% |
| St. Thomas township | 6,027 | +1.8% | 51.9 | 6.7% |
| Montgomery township | 5,823 | +1.4% | 67.4 | 8.7% |
| Quincy township | 5,283 | −0.5% | 45.2 | 5.9% |
| Peters township | 4,473 | +0.3% | 55.8 | 7.2% |
| Greencastle borough | 4,222 | −0.1% | 1.588 | 0.2% |
| Letterkenny township | 2,550 | +3.7% | 70.4 | 9.1% |
| Fannett township | 2,498 | +0.5% | 68.2 | 8.8% |
Show the other 7 subdivisions
| Name | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Lurgan township | 2,208 | 0% | 32.7 |
| Metal township | 1,772 | +0.5% | 44.5 |
| Mont Alto borough | 1,563 | −0.9% | 0.563 |
| Mercersburg borough | 1,492 | −1% | 0.902 |
| Shippensburg borough | 1,181 | +1% | 0.717 |
| Warren township | 330 | +1.2% | 30.6 |
| Orrstown borough | 210 | −1.9% | 0.064 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each subdivision inside Franklin County. Land: 2026 Census Gazetteer. How communities are listed.
Metropolitan area
Franklin County is a central county of the Chambersburg, PA Metropolitan Statistical Area. Franklin County is the area’s only county equivalent, so the metro area has the same 772.3 square miles of land. By combined land it ranks #310 of 393 metropolitan areas, and #276 by population. It belongs to the Washington-Baltimore-Arlington, DC-MD-VA-WV-PA Combined Statistical Area.
ZIP codes
31 ZIP Code Tabulation Areas have land in Franklin County; 28 of them have most of their land inside the county, and the others mainly cover neighboring areas.
17021172011720217210172141721717219172201722117222172241722517232172351723617237172401724417246172471725017251172521725417257172611726217263172651726817271
ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.
Counties bordering Franklin County
Franklin County shares a land border with 8 county equivalents, including 2 in Maryland. It has more land than 7 of them. The largest neighbor is Huntingdon County (874.6 mi²) and the smallest is Juniata County (391.4 mi²). Together with its neighbors, Franklin County forms a block of 5,209.8 mi² of land, of which it holds 14.8%.
| Bordering county equivalent | Land mi² | Size vs. Franklin | Compare |
|---|---|---|---|
| Huntingdon County | 874.6 | 1.1× larger | Compare |
| Frederick CountyMaryland | 660.7 | 1.2× smaller | Compare |
| Perry County | 551.5 | 1.4× smaller | Compare |
| Cumberland County | 545.5 | 1.4× smaller | Compare |
| Adams County | 518.6 | 1.5× smaller | Compare |
| Washington CountyMaryland | 457.8 | 1.7× smaller | Compare |
| Fulton County | 437.6 | 1.8× smaller | Compare |
| Juniata County | 391.4 | 2× smaller | Compare |
How big is Franklin County compared with U.S. states?
Franklin County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.3 times as much. Pennsylvania’s county land could hold about 58 areas the size of Franklin County.
Another way to picture it: the same land area would fill a square about 27.8 miles (44.7 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.
State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.
What stands out about Franklin County?
Franklin County has more land than 2,097 of the other 3,221 county equivalents in the dataset.
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 Franklin County at #1,235 nationally by total area, 110 places farther from the top than its land rank. Other county equivalents gain more area when their water measurements are included.
Its water share is 0.1%, compared with a national county-equivalent median of 1.2% — 1.1 percentage points lower. 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 Franklin County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #1124 | Keya Paha County, Nebraska | 772.9 | Compare |
| #1125 | Franklin County, Pennsylvania | 772.3 | This county |
| #1126 | Lonoke County, Arkansas | 771.7 | Compare |
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 39.926959, -77.719273. 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: 2,000,193,434 m²; AWATER: 1,553,435 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.
Common questions
How big is Franklin County?
Franklin County, Pennsylvania has 772.3 square miles (2,000.2 km²) of land and 0.6 square miles of water, for a total area of 772.9 square miles. It ranks #1125 of 3,222 U.S. county equivalents by land area.
Is Franklin County the largest county in Pennsylvania?
No. Franklin County ranks #27 of 67 in Pennsylvania by land area. The largest is Lycoming County, with 1,228.9 square miles of land.
What counties border Franklin County?
Franklin County shares a land border with Washington County, Maryland, Fulton County, Cumberland County, Huntingdon County, Adams County, Perry County, Juniata County, and Frederick County, Maryland.
What is the population of Franklin County?
The Census Bureau estimates Franklin County had 160,652 residents on July 1, 2025, ranking #437 of 3,222 county equivalents. That is 208 people per square mile of land.
What is the county seat of Franklin County?
The county seat of Franklin County is Chambersburg.
What cities and towns are in Franklin County?
Franklin County has 22 county subdivisions (cities, towns and townships). The most populous five are Chambersburg borough, Greene township, Antrim township, Washington township, and Guilford township.
Is Franklin County part of a metropolitan area?
Yes. It is a central county of the Chambersburg, PA Metropolitan Statistical Area.
How many ZIP codes are in Franklin County?
31 ZIP Code Tabulation Areas have land in Franklin County, and 28 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does Franklin County compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 1.3 times as much land.
How many acres of land are in Franklin County?
The land measurement converts to approximately 494,259 acres. Including water, total area is approximately 494,643 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.