Rising nearly 5,000 feet above Yosemite Valley and 8,800 feet above sea level, Half Dome is a Yosemite icon and a great challenge to many hikers. The 14 to 16 mile round-trip hike to Half Dome is not for you if you're out of shape or unprepared. You will be gaining elevation (for a total of 4,800 feet) most of your way to the top of Half Dome. Most would say the reward is worth the effort.