The immense First and Third Flatirons rise over Boulder like unmistakable landmarks signaling the presence of the Rockies. They also offer the Flatirons’ best climbing, with over 40 different routes on fantastic quality rock. Our guides, from the Colorado Mountain School, have the expertise to safely show you the ultimate Flatirons experience. The Colorado Mountain School (CMS) has been guiding and instructing climbers on the Flatirons for over two decades. They love guiding in Boulder Mountain Park and know the climbs and trails like ‘the backs of their hands.’ CMS is accredited by the American Mountain Guides Association and has more AMGA and IFMGA certified guides than any other guide service in Colorado.