Rock Run begins in the acidic wetlands along the border of Pennsylvania’s Lycoming and Sullivan counties, flowing in a generally southwestern direction until it flows into Lycoming Creek near Ralston. This is not the only Rock Run in Pennsylvania, a state whose early explorers and settlers were particularly unimaginative when naming waterways, but it is probably the most beautiful of those bearing the name.
The headwaters of Rock Run’s North Branch are in the Loyalsock Sate Forest’s Devils Elbow Natural Area with its extensive wetlands of emergent vegetation and wooded wetlands dominated by eastern hemlock –
Leaving those wetlands Rock Run becomes a high-gradient free-stone stream as it begins its descent from the Allegheny Plateau, losing 1000 feet in elevation in its first five miles. After Yellow Dog Run joins Rock Run, the stream’s gradient diminishes and the nature of its bed changes. Now segments of gravel bottom alternate with extensive sections of bedrock.
Some of the potholes contain smaller rocks of the sort that, swirling around during high water events, wore away the bedrock to create those potholes–
Rock Run’s beauty has attracted visitors for decades. Unfortunately, about 25 years ago the valley began to attract society’s less desirable elements and so camping has been prohibited in this part of the Loyalsock State Forest.
Further along, Rock Run is joined by Miners Run (featured in this post) which has its own waterfalls –In addition to its headwaters in the Devils Elbow Natural Area, Rock Run borders the 7,500 acre McIntyre Wild Area. The wild area contains three other streams: Hounds Run, Dutchmans Run and Abbotts Run with waterfalls of their own.