Best viewed at a resolution of at least 1280x1024 or higher. Supports Chrome, Firefox, IE9+, Opera, and Safari. Inspired by this map by Johnathan Clayton posted at Ultrarunnerpodcast.com/. Extra thanks to Stan Jensen at (run100s.com), Nick Marshall, John Price, and many others on the Ultralist for filling in some gaps. Even so, there are many more old 100mi races that are yet to be catalogued!
Know a 100mi race from past or present that you don't see? Email me on the Ultralist with additions or errors. Please include the Ultra name, location, and years held if known.