Pennsylvania Route 590 ('PA 590) is a 45.0-mile (72.4 km) long state highway located in Lackawanna, Wayne, and Pike counties in Pennsylvania. The western terminus is at PA 435 in Elmhurst Township. The eastern terminus is at PA 434 in Lackawaxen Township.

Part of the route in Wayne County follows the abandoned towpath and bed of the Delaware and Hudson Canal, a National Historic Landmark.

PA 590 begins at an intersection with PA 435 in Elmhurst Township, Lackawanna County, heading southeast on a two-lane undivided road. The route runs through forested areas with some homes, curving east into Roaring Brook Township and passing to the north of Elmhurst Reservoir. The road heads northeast through more forests with some fields and residences, crossing into Madison Township and passing to the northwest of Curtis Reservoir on Hamlin Road as it continues into Jefferson Township. PA 590 runs through more rural areas and passes over I-84, curving to the east and heading through Drinker before turning to the south.

PA 590 enters Salem Township in Wayne County and becomes Hamlin Highway, continuing northeast through wooded areas with some homes and intersecting the eastern terminus of PA 690 in Hollisterville. The road runs through more rural areas of residences and comes to a junction with the eastern terminus of PA 348. At this point, the route turns to the east and heads into agricultural areas with some woods and residential and commercial development. PA 590 gains a center left-turn lane and passes near more businesses as it comes to an intersection with PA 191/PA 196 in Hamlin. The road loses the center left-turn lane past this intersection and continues into forested areas before heading through more woodland with some farm fields and homes, turning east-northeast near Peetona. The route curves more to the east as it heads through Arlington. PA 590 heads to the northeast again as it enters Paupack Township and becomes Purdytown Turnpike. The road heads through forested areas with some farmland and residences, passing through Lakeville. The route turns east and heads through Uswick entering dense forests. PA 590 turns northeast and passes to the northwest of Lake Wallenpaupack. The road heads into wooded areas of residential development and crosses into Palmyra Township, turning to the southeast. The route heads through more forests to the north of the lake and heads east to an intersection with US 6 in Wilsonville.

Here, PA 590 turns north for a concurrency with US 6 on Welwood Avenue, heading northeast through some development as a three-lane road with a center left-turn lane. The road loses the turn lane and heads through wooded areas before crossing into Hawley. US 6/PA 590 becomes Bellemonte Avenue and turns northwest into residential areas, heading to the west and becoming Spring Street. The two routes turn north onto Main Avenue and pass through the commercial downtown of Hawley, crossing the Middle Creek before heading across the Stourbridge Railroad and the Lackawaxen River. The road passes more businesses before coming to an intersection where US 6 heads to the west and PA 590 heads southeast on Hudson Street. The route heads through wooded areas with some homes to the northeast of the Lackawaxen River. The road turns north-northeast away from the river and heads back into Palmyra Township, turning to the east.

PA 590 continues into Lackawaxen Township in Pike County and becomes an unnamed road, heading into forested areas and turning north before making a turn to the southeast. The road winds through more forests with some residential developments, heading northeast before a turn to the east. The route continues through rural areas, heading northeast briefly before turning to the southeast, passing through Bohemia. PA 590 runs through more forests with some homes and comes to the community of Rowland, where it turns northeast and runs to the northwest of the Lackawaxen River. The road winds east through forests to the north of the river, heading northeast before turning southeast to cross the Lackawaxen River. The route heads into rural areas of development a short distance to the west of a Norfolk Southern railroad line, crossing the Stourbridge Railroad again and entering the community of Lackawaxen. PA 590 turns southwest and continues south into dense forests. The road continues south and heads through more forests with some homes. PA 590 comes to its eastern terminus at an intersection with PA 434 in Greeley, where the road becomes a part of PA 434.