The list of Interstate Highways in Pennsylvania encompasses 23 Interstate Highways—12 primary routes and 11 auxiliary routes—which exist entirely or partially in the U.S. state of Pennsylvania. In Pennsylvania, most of the Interstate Highways are maintained by the Pennsylvania Department of Transportation (PennDOT). Some stretches are also maintained by the Pennsylvania Turnpike Commission, Delaware River Port Authority, the Delaware River Joint Toll Bridge Commission, and two short stretches maintained by the New York State Department of Transportation (these being the Delaware River bridge on Interstate 84 (I-84) and a short stretch of the future I-86 in Bradford County). Interstate Highways make up three percent of all roadway lane miles in Pennsylvania and have a combined length of within the state. Twenty-four percent of all vehicle traffic is on the Interstate System.
<Gallery mode=packed> File:Entering Pennsylvania on I-86 west.jpg|Entering Pennsylvania on I-86 westbound in Erie County File:2020-07-12 09 45 32 View south along Interstate 95 (Pennsylvania Turnpike Delaware River Extension) at Exit 40 (Interstate 276 WEST-Pennsylvania Turnpike, Harrisburg) in Bristol Township, Bucks County, Pennsylvania.jpg|I-95 at I-276 exit File:Int90eRoadPA-Exit22AB-Int79ns (32528708502).jpg|I-90 at I-79 exit File:Interstate 78 and 81 junction, northbound.jpg|I-81 at I-78 exit File:2015-12-14 12 41 37 View north along Interstate 99 and U.S. Route 220 at Exit 73 (East U.S. Route 322, Penn State University, State College) in College Township, Pennsylvania.jpg|I-99 to I-80 File:Interstate 176 northern terminus.JPG|I-176 end at US 422 File:Pavement markings I-283 & I-83.jpg|I-83 and I-283 File:I-476 north of US 1.JPG|I-476 north of US 1 File:376 00.jpg|I-376 in Pittsburgh File:Breezewood Exit.jpg|I-70 and I-76 at eastern split File:I-76 WB at I-676-US 30 interchange.jpeg|I-76 approaching I-676 file:Interstate7079Washington.jpg|I-79 at I-70 </Gallery>