The Royal Arch Trail is a 3.1-mile out-and-back trail that is heavily trafficked and located near Boulder. The course features beautiful wildflowers and is used for hiking, running, and snowshoeing from March until October. The leading destination of this trail is the Royal Arch which is a favorite among the locals. Just follow the signs for Royal Arch and when you get to the flagstone staircase, you can be more confident that you're heading in the right direction. The Sentinel Pass climb presents an elevation gain which will also signify that you're about a half-mile away from the Royal Arch. The hike is challenging with gorgeous and breathtaking views. This trail has a lot of stairs and it becomes a little technical in a couple of spots closer to the end.