County outline
Where Butler County is located
Area breakdown
Land accounts for 99.2% of Butler County’s measured area and water for 0.8%. Its combined area converts to 2,060.8 square kilometers or approximately 509,223 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 789.482 | 2,044.749 | 505,268.5 |
| Water | 6.179 | 16.004 | 3,954.6 |
| Total | 795.661 | 2,060.753 | 509,223 |
How Butler County compares
By original Census land area, Butler County ranks #25 of 67 in Pennsylvania and #1092 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 1.208 times the Pennsylvania county-equivalent median of 653.3 square miles. It accounts for 1.8% of the combined county land area in the state.
See the complete Pennsylvania ranking · What counts as a county equivalent?
Population and density of Butler County
The Census Bureau estimates that 200,169 people lived in Butler County on July 1, 2025. That ranks #360 of 3,222 county equivalents nationally and #19 of 67 in Pennsylvania. Since the April 1, 2020 estimates base of 193,716, the population has grown by 6,453 (+3.3%), compared with +0.4% for Pennsylvania as a whole.
With 789.5 square miles of land, that is 254 people per square mile (98 per km²), placing Butler County #567 nationally for density and #21 in Pennsylvania. The median county equivalent has 47 people per square mile; the Pennsylvania median is 137. Put another way, there are about 2.5 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 194,026 | 196,738 | 197,374 | 198,657 | 199,300 | 200,169 |
| Change | — | +2,712 | +636 | +1,283 | +643 | +869 |
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 Butler County
Butler County is divided into 57 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 Cranberry township, with 35,244 residents (17.6% of the county). The largest by land is Slippery Rock township, at 25.8 mi², or 3.3% of the county’s land. The county seat, Butler township, has 16,902 residents. Among those with at least 1,000 residents in 2020, Lancaster township grew fastest since then (+36.1%).
| County subdivision | Population 2025 | Since 2020 | Land mi² | Share of county land |
|---|---|---|---|---|
| Cranberry township | 35,244 | +6.6% | 22.9 | 2.9% |
| Butler townshipCounty seat | 16,902 | −1.8% | 21.6 | 2.7% |
| Adams township | 15,927 | +7.3% | 22.3 | 2.8% |
| Butler cityCounty seat | 12,879 | −4.6% | 2.719 | 0.3% |
| Slippery Rock township | 8,349 | +24.7% | 25.8 | 3.3% |
| Buffalo township | 8,214 | +4.1% | 24.1 | 3.1% |
| Center township | 7,778 | −1.4% | 24.4 | 3.1% |
| Middlesex township | 7,513 | +10% | 23.1 | 2.9% |
| Jackson township | 6,585 | +34.7% | 21.7 | 2.7% |
| Jefferson township | 5,096 | −2.6% | 22.9 | 2.9% |
| Penn township | 4,890 | −2.5% | 24.3 | 3.1% |
| Summit township | 4,308 | −4% | 22.4 | 2.8% |
| Connoquenessing township | 4,151 | −2.6% | 22.7 | 2.9% |
| Zelienople borough | 3,752 | −4.2% | 2.053 | 0.3% |
| Lancaster township | 3,734 | +36.1% | 23 | 2.9% |
Show the other 42 subdivisions
| Name | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Slippery Rock borough | 3,551 | +11.5% | 1.645 |
| Forward township | 3,412 | +8.2% | 23 |
| Winfield township | 3,287 | −2.1% | 23.8 |
| Seven Fields borough | 2,864 | −2.2% | 0.805 |
| Clinton township | 2,824 | −2.5% | 23.6 |
| Oakland township | 2,707 | −2.6% | 23.7 |
| Franklin township | 2,602 | +0.3% | 21.3 |
| Clay township | 2,473 | −2.8% | 25.1 |
| Clearfield township | 2,358 | −3.3% | 23.7 |
| Muddy Creek township | 2,168 | −1.9% | 22.6 |
| Fairview township | 1,943 | −1.2% | 24.2 |
| Donegal township | 1,775 | −2.6% | 23.2 |
| Evans City borough | 1,670 | −4.4% | 0.818 |
| Mars borough | 1,391 | −3.9% | 0.47 |
| Saxonburg borough | 1,368 | −4.3% | 0.906 |
| Worth township | 1,357 | −2.8% | 25 |
| Concord township | 1,354 | −3.6% | 24.2 |
| Washington township | 1,236 | −3.4% | 24.9 |
| Brady township | 1,184 | −3% | 17 |
| Marion township | 1,110 | −2.6% | 25.4 |
| Prospect borough | 1,086 | −3.9% | 4.082 |
| Cherry township | 1,041 | −0.8% | 25.6 |
| Mercer township | 1,002 | −0.8% | 13 |
| Harmony borough | 905 | −4.2% | 0.394 |
| Chicora borough | 870 | −4.3% | 0.533 |
| Venango township | 839 | −4.2% | 21 |
| Connoquenessing borough | 809 | +19.9% | 1.355 |
| Harrisville borough | 782 | −4.2% | 0.804 |
| East Butler borough | 728 | −4.6% | 1.043 |
| Valencia borough | 681 | +25.6% | 0.34 |
| Allegheny township | 605 | −2.1% | 25 |
| Parker township | 562 | −2.9% | 22.9 |
| Bruin borough | 401 | −4.8% | 1.825 |
| Callery borough | 335 | −4.8% | 0.537 |
| West Liberty borough | 320 | −4.2% | 3.841 |
| Eau Claire borough | 290 | −4.9% | 1.275 |
| Portersville borough | 220 | −4.3% | 0.795 |
| Fairview borough | 177 | +4.1% | 0.113 |
| West Sunbury borough | 174 | −4.4% | 0.11 |
| Petrolia borough | 171 | −4.5% | 0.395 |
| Karns City borough | 160 | −4.2% | 0.363 |
| Cherry Valley borough | 55 | −5.2% | 2.819 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each subdivision inside Butler County. Land: 2026 Census Gazetteer. How communities are listed.
Metropolitan area
Butler County is a central county of the Pittsburgh, PA Metropolitan Statistical Area. Its 8 county equivalents have 2,421,992 residents on 5,640.3 square miles of land; Butler County accounts for 14% of the land and 8.3% of the residents. By combined land it ranks #38 of 393 metropolitan areas, and #28 by population. It belongs to the Pittsburgh-Weirton-Steubenville, PA-OH-WV Combined Statistical Area.
| County equivalent | Population 2025 | Land mi² |
|---|---|---|
| Allegheny County | 1,225,035 | 730 |
| Westmoreland County | 349,324 | 1,027.7 |
| Washington County | 210,802 | 857 |
| Butler County | 200,169 | 789.5 |
| Beaver County | 166,032 | 434.7 |
| Fayette County | 123,021 | 790.8 |
| Lawrence County | 83,911 | 357.4 |
| Armstrong County | 63,698 | 653.3 |
ZIP codes
37 ZIP Code Tabulation Areas have land in Butler County; 31 of them have most of their land inside the county, and the others mainly cover neighboring areas.
15044150861600116002160201602216023160241602516027160291603016033160341603516037160381604016041160451604616048160491605016051160521605316055160561605716059160611606316066161271622916373
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 Butler County
Butler County shares a land border with 7 county equivalents. It has more land than every one of them. The largest neighbor is Allegheny County (730 mi²) and the smallest is Lawrence County (357.4 mi²). Together with its neighbors, Butler County forms a block of 4,912.5 mi² of land, of which it holds 16.1%.
| Bordering county equivalent | Land mi² | Size vs. Butler | Compare |
|---|---|---|---|
| Allegheny County | 730 | 1.1× smaller | Compare |
| Venango County | 674.3 | 1.2× smaller | Compare |
| Mercer County | 672.5 | 1.2× smaller | Compare |
| Armstrong County | 653.3 | 1.2× smaller | Compare |
| Clarion County | 600.8 | 1.3× smaller | Compare |
| Beaver County | 434.7 | 1.8× smaller | Compare |
| Lawrence County | 357.4 | 2.2× smaller | Compare |
How big is Butler County compared with U.S. states?
Butler 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 57 areas the size of Butler County.
Another way to picture it: the same land area would fill a square about 28.1 miles (45.2 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 Butler County?
Butler County has more land than 2,130 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 Butler County at #1,191 nationally by total area, 99 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 0.8%, compared with a national county-equivalent median of 1.2% — 0.4 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 Butler County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #1091 | Oregon County, Missouri | 789.8 | Compare |
| #1092 | Butler County, Pennsylvania | 789.5 | This county |
| #1093 | Comanche County, Kansas | 788.3 | 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 40.913847, -79.918978. 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: 2,044,750,101 m²; AWATER: 16,004,634 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 Butler County?
Butler County, Pennsylvania has 789.5 square miles (2,044.7 km²) of land and 6.179 square miles of water, for a total area of 795.7 square miles. It ranks #1092 of 3,222 U.S. county equivalents by land area.
Is Butler County the largest county in Pennsylvania?
No. Butler County ranks #25 of 67 in Pennsylvania by land area. The largest is Lycoming County, with 1,228.9 square miles of land.
What counties border Butler County?
Butler County shares a land border with Armstrong County, Allegheny County, Lawrence County, Venango County, Beaver County, Mercer County, and Clarion County.
What is the population of Butler County?
The Census Bureau estimates Butler County had 200,169 residents on July 1, 2025, ranking #360 of 3,222 county equivalents. That is 254 people per square mile of land.
What is the county seat of Butler County?
The county seat of Butler County is Butler.
What cities and towns are in Butler County?
Butler County has 57 county subdivisions (cities, towns and townships). The most populous five are Cranberry township, Butler township, Adams township, Butler city, and Slippery Rock township.
Is Butler County part of a metropolitan area?
Yes. It is a central county of the Pittsburgh, PA Metropolitan Statistical Area, which has 8 county equivalents and 2,421,992 residents.
How many ZIP codes are in Butler County?
37 ZIP Code Tabulation Areas have land in Butler County, and 31 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does Butler 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 Butler County?
The land measurement converts to approximately 505,268 acres. Including water, total area is approximately 509,223 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.