Trail running sounds like this intimidating extreme sport for ultra runners, but really it’s defined as any sort of running on an unpaved surface.
If there’s a nearby dirt or grass path at your local park, that’s trail running. If you run on the street or on a paved trail or road, that’s called road running.
Trail running gets a large part of its allure from the ability of a runner to be out in nature without any potential distractions getting in your way. It’s just you and the open trail.
For more information about trail running, check out the Dick’s Sporting Goods blog.