Ultramarathons in Castle Rock

Saturday, August 29 · Castle Rock, Colorado

The Rock Hawk 50K takes place in late August on the trail systems of Castle Rock's Miller Park, about 30 miles south of Denver. The course covers 31.2 miles with 3,325 feet of climbing, following a loop format where runners hit two main aid stations multiple times throughout the race. The trails here aren't overly technical but offer consistent rolling terrain that keeps you working. Much of the route follows the Ridgeline Trail system, providing wide-open views of the Colorado Front Range while moving through a mix of open spaces and scattered tree cover. At around 6,000 feet elevation, late August conditions can range from cool mornings to warm afternoons, with limited shade on exposed sections. The course returns to the start/finish area at the halfway point, offering a mental break and access to drop bags. This race works well for runners looking for a solid introduction to 50K distance or those wanting a good training effort without extreme technicality. The rolling nature means you're rarely on flat ground for long, so runners comfortable with sustained moderate effort rather than big climbs and descents will feel most at home. The 9-hour cutoff is generous, but the consistent terrain keeps most people moving steadily throughout.