List of quadrant routes in Northumberland County, Pennsylvania

Quadrant Routes in Pennsylvania are maintained by the Pennsylvania Department of Transportation. This article lists all the routes and their termini in Northumberland County. As is the case with the other counties in the state, the route numbers start in the northeast quadrant and go clockwise from the 1000s to the 4000s; however, due to the unique shape of the county, there are neither explicit quadrant dividers nor numbering order schemes. For example, the 1000s are restricted to the "U.P." (north of the north branch Susquehanna), while the 4000s are around and below Sunbury. Odd numbered roads travel south to north. Even numbered roads travel west to east.