The headwaters of the Lackawanna River are in the glaciated plateau physiographic province of the Appalachian Mountains. However, the Lackawanna Valley is in the northernmost part of the ridge and valley physiographic province. The river also flows through a portion of the Northern Anthracite Coal Field. The Lackawanna Valley is part of the Lackawanna/Wyoming Syncline, which is a large syncline in the Allegheny Front and is the main geological feature of the watershed. The syncline is canoe-shaped, with a length of and a width of . The crests of the anticlines on both sides have been eroded away. An escarpment known as Campbells Ledge is located near the river's mouth, where the Susquehanna Valley enters the 55-mile-long Lackawanna/Wyoming Valley.