The origins of the Pennsylvania highway system began with the signing of an act by Governor Samuel W. Pennypacker that created the Department of Highways, the predecessor to PennDOT. In 1911, the highway system became official through the Sproul Act, which gave control of over 8,000 miles of highway to the Department of Highways. In the 1930's, the Penrose Rural Roads Act permitted over 20,000 miles to Pennsylvania's government. Under Governor Gifford Pinchot, roads in rural areas began to be paved.
The historic system of Pennsylvania routes came to comprise the US Highways that are present within the state of Pennsylvania. This group of highways has a length of 3,610 miles in total. Although identified as US Routes, they are maintained by the Pennsylvania Department of Transportation. While some routes are mostly or completely contained within state boundaries, other historic PA routes are only segments of routes that connect to other states and even to the west coast.
On the map, the series of Pennsylvania highways are visible. Many routes do not run independently for the majority of their length. There are instances where two routes may share a common section. For example, there is a concurrency of US Route 1 and US Route 13 in Philadelphia. An historic PA highway could also share a common roadway with a highway on a different system level, such as part of US Route 22 that was used to create Interstate 78. US Route 422 stands out as a highway that is divded into two separate segments, with one in eastern Pennsylvania that is completely separate from a western segment going into Ohio.
The intent of this map is to give a sense of the major highway system in Pennsylvania before the Pennsylvania Turnpike and Interstate Highway System were inplemented in 1940 and after. However, that is challenging to accomplish because the US Route highways of today do not always align with their original placements. The construction of the IHS demonstrated the advantages of limited access and higher speeds, which has led to many stretches of the US Highway System being realigned to allow for more lanes, ramps and fewer access points.
The dates you will see on the information windows that pop up on the map when viewing the road segments will not all fit within the range stated in this page's subtitle. This also relates to the re-construction and realignments of various sections of the highways. The dates that are used in the information popups come from the Pennsylvania Department of Transportation. Since most of the roads existed before they became elevated to US Route status, the dates do not likely reflect their original construction.