Trailmaker.org is an app for viewing historical, cultural, architectural, natural, and commercial markers in trails and surrounding areas - it is also an open source framework available on GitHub, which includes a website for administration of the trails and markers. It has been used in the Appalachian Trail area of PA, initially developed at the University of Pittsburgh at Bradford, with many local people and organizations in Bradford, Warren, Smethport, and Kane Pennsylvania. TrailMaker.org has subsequently been used around the US and in Europe. This app showcases the Appalachian Trail area, and the files on GitHub allow anyone to replicate this app and the curation/monitoring of trails.