Sentinel Rock proudly stands above Yosemite Valley and beckons your attention. Sentinel Rock gets its name from its resemblance to a watchtower. When viewed from the western side, the tower-like appearance is most evident. The formation is one of the most dominating rock formations in the center of Yosemite Valley. Located opposite of Yosemite Falls, Sentinel Rock towers over 3,000 feet above the valley floor.