Pennsylvania Route 423 (PA 423) is a state route in Monroe and Wayne Counties in Pennsylvania. It runs for 14.32 miles (23.05 km), crossing through the Pocono Mountains from PA 940 in Pocono Pines to PA 191 in South Sterling. The route runs southwest-northeast through forested areas of the Pocono Mountains as a two-lane undivided road. In Tobyhanna, PA 423 has an interchange with Interstate 380 (I-380) and an intersection with PA 611. Farther northeast, the route crosses PA 196 in Gouldsboro. PA 490 was designated in 1928 to run from U.S. Route 611 (US 611) in Tobyhanna northeast to PA 90 (now PA 191) in . In the 1930s, the route was extended and realigned to run from PA 940 in Pocono Pines to PA 90 in South Sterling. PA 490 became PA 423 in the 1960s.