ABSTRACT Trails are essential transportation infrastructure supporting access to protected natural areas and providing recreation to hikers, runners, cyclists, equestrians, motorists, and many more worldwide. The slope of trails and their surrounding terrain influences physical trail sustainability and difficulty of travel. This research examines methods for using high-resolution digital elevation models to measure terrain steepness near trails and along trails or potential trail routes by comparing geographic information system (GIS) derived measurements to field measurements from the Appalachian Trail. The analysis validates the use of digitally derived trail terrain metrics and provides guidance to improve their utility in future trail planning and assessment efforts.