| Butler | 13,757 |
| Fernway | 12,414 |
| Homeacre-Lyndora | 6,906 |
| Shanor-Northvue | 5,051 |
| Meridian | 3,881 |
| Zelienople | 3,812 |
| Slippery Rock | 3,625 |
| Fox Run | 3,282 |
| Seven Fields | 2,887 |
| Meadowood | 2,693 |
| Oak Hills | 2,333 |
| Slippery Rock University | 1,898 |
| Evans City | 1,833 |
| Mars | 1,699 |
| Saxonburg | 1,525 |
| Nixon | 1,373 |
| Prospect | 1,169 |
| Chicora | 1,043 |
| Unionville | 962 |
| Harrisville | 897 |
| Harmony | 890 |
| East Butler | 732 |
| Lake Arthur Estates | 594 |
| Valencia | 551 |
| Connoquenessing | 528 |
| Bruin | 524 |
| Callery | 394 |
| West Liberty | 343 |
| Eau Claire | 316 |
| Portersville | 235 |
| Petrolia | 212 |
| Karns City | 209 |
| Fairview | 198 |
| West Sunbury | 192 |
| Cherry Valley | 66 |
| Chairman | Leslie Osche |
| Commissioner | Kimberly Geyer |
| Commissioner | Kevin Boozel |
| President | Al Vavro |
| Vice President | Jennifer Cummings |
| Director | John Conrad |
| Director | Jennifer Daniels-Wells |
| Director | Regenold Griffin |
| Director | Bill Halle |
| Director | Gary Shingleton |
| Director | Nina Teff |
| Director | Mary Waggoner |
Butler County has long been one of the most consistently Republican counties in Pennsylvania. The last Democratic presidential candidate to win it was Lyndon B. Johnson in 1964, when he won a national landslide and carried all but four counties in the state. In the 2000 U.S. presidential election, Republican George W. Bush received 62%, while Democrat Al Gore received 35%. In the 2004 U.S. presidential election, the county was carried by Republican George W. Bush 64% to Democrat John Kerry 35%. In the 2008 U.S. presidential election, the county was carried by Republican John McCain 63% to Democrat Barack Obama 35%. Since 2008, Butler County has continually given Republican nominees support in the mid-60s, with both Mitt Romney Mitt Romney and Donald Trump Donald Trump receiving around 66% of the vote in 2012, 2016, and 2020.
