The West Rim Trail is a 30 mile hiking trail located adjacent to the Western Rim of Pennsylvania's Grand Canyon. The northern section of the canyon is about 800 feet deep and about 2,000 feet from rim to rim. The exposed rock is estimated to be more than 350 million years old. Most of the important geologic process which formed the canyon as it now exists occurred less than 20,000 years ago. Before glacial activity took place in the present Canyon area, the headwaters of Pine Creek took a northeastern drainage course. Glaciers deposited a blanket og gravel, sand and clay blocking the flow of Pine Creek. This natural dam forced Pine Creek to reverse its flow and drain to the south. This overflow cut through the drainage divide and formed the canyon. The trail offers spectacular views of the Canyon. In some spots the trail follows the very rim of the Canyon, so watch your step.