 Pennsylvania Route 45 Truck is a truck route in Mifflinburg, Union County.Narrow streets within the borough are avoided by this designation, and a complicated intersection with Pennsylvania Route 304, which does not contain turning lanes, is bypassed.The route begins at PA 304 south of Mifflinburg by heading west along SR 3004 (Red Ridge Road) before turning north onto Pennsylvania Route 104 and ending at PA 45.