Mon River Trail South is a hiking and biking trail in Marion County and Monongalia County, West Virginia. It is within Pricketts Fort State Park. It is 17.8 miles long and begins at 823 feet altitude. Traveling the entire trail is 35.6 miles with a total elevation gain of 1,418 feet. The Little Falls Post Office (elevation 853 feet) post office can be seen along the trail.