The Wapack and Back Trail Races consist of a 50 mile ultramarathon and an end-to-end trail race run on the 21.5 mile Wapack Trail (www.wapack.org). Leading from Mt Watatic in Massachusetts to North Pack Mt in Greenfield, NH, the rocky ledges of this technical trail (approx 4600 ft elevation gain in each direction, 50 miler is around 10,800' climb) afford views of the Boston skyline to the east, Berkshire and Green Mountains to the west and White Mountains to the north. Ultrarunners who complete the 43 mile out and back section will be receive a finishing time and be listed in the results. Runners "only" looking to run the 43 mile race can still sign up for the 50 mile race and stop at the start/finish. Four aid stations (which ultrarunners pass twice) will provide water, electrolyte drink, sugary and salty snacks. Post-race refreshments will be provided.