Arethusa Falls and Frankenstein Cliff Trail is a 4.2 mile moderately trafficked loop trail located near Bartlett, New Hampshire that features a waterfall and is rated as difficult. The trail offers a number of activity options and is best used from March until October. Dogs are also able to use this trail. Directions from Bartlett, NH: Travel north approximately 12 miles on US 302 to the park entrance. Soon after entering the park, you will see a parking lot on your left specifically for this waterfall trail.