Mount Warner Trailhead, Hadley, Massachusetts Mount Warner Trail is an easy hike covering 2.2 miles with 262 feet of elevation gain. The trail is a loop, withthe main loop, Salamander Crossing Trail, rebuilt in 2014. Hikers can wander the gentle slopes of this 500-foot hill overlooking the Connecticut River Valley, wherevernal pools shelter an array of animal and plant species, and in spring, you may spot frogs and salamanders that emerge to reproduce in these seasonal wetlands. The trail ascends through oak, beech, and other hardwoods, with evergreen groves beginning further upslope. A notable feature is a massive glacial erratic known as “Lou’s Rock,” left by retreating glaciers some 12,000 years ago.