10 am. The 4th Annual Union Half Marathon and Relay will start at the Visitor Center in Big Stone Gap, VA. The course will utilize the paved Greenbelt Trail in Big Stone and then unite with the Powell River Trail in Appalachia, VA. Participants will be able to go through the two old train tunnels that make up the Powell River Trail. All completing participants will receive a unique finisher’s medal and a race t-shirt. If you can't run a full half marathon, consider the 2-person relay.