The West Branch Susquehanna River is one of the two principal branches, along with the North Branch, of the Susquehanna River in the Northeastern United States. The North Branch, which rises in upstate New York, is generally regarded as the extension of the main branch, with the shorter West Branch being its principal tributary. The West Branch, which is long, is entirely within the state of Pennsylvania, draining a large mountainous area within the Allegheny Plateau in the western part of the state. Along most of its course it meanders past mountain ridges and through water gaps, forming a large zigzag arc through central Pennsylvania around the north end of the Allegheny Mountains. In colonial times the river valley provided an important route to the Ohio River valley. In the 19th century, its lower valley became a significant industrial heartland of Pennsylvania. In the 20th century, the upper reaches of the West Branch turned a yellow/orange color due to sulfurous drainage from nearby and abandoned deep bituminous coal mines. Course The West Branch rises on the west side of the Alleghenies in northwestern Cambria County, just outside the borough of Carrolltown. It flows generally north, crossing the eastern corner of Indiana County at Cherry Tree, then into southern Clearfield County. Near Mahaffey it turns generally northeast and flows past Curwensville and Clearfield. In northern Clinton County it turns to the southeast to Lock Haven. At Lock Haven, it turns east, flowing through the West Branch Susquehanna Valley along the foot of Bald Eagle Mountain ridge past Williamsport, the largest city on the river, then turns south at the end of the ridge. From there it winds around Muncy, emerging from a water gap between Montour Ridge and Shamokin Mountain and joining the north (main) branch of the Susquehanna from the northwest approximately north of Sunbury. Tributaries From its upper reaches to its lower reaches, it receives: Chest Creek from the south at Mahaffey Anderson Creek from the west in Curwensville Clearfield Creek from the south east of Clearfield Moshannon Creek from the south south of Karthaus Sinnemahoning Creek from the northwest at Keating Fish Dam Run from the south southwest of Renovo, Pennsylvania Bald Eagle Creek from the southwest at Lock Haven Pine Creek and Larrys Creek from the north near Jersey Shore Lycoming Creek from the north at Williamsport Loyalsock Creek from the northeast at Montoursville Muncy Creek from