How many people visit Rainbow Bridge each year? An average of 200,000 - 300,000 people visit the bridge each year. The vast majority travel by tour boat and private vessel to get here, although a few adventurous visitors hike 16-18 miles around. Navajo Mountain to enter the monument. When was Rainbow Bridge first discovered? Definite date unknown. Rainbow Bridge was likely first observed by a local Native American inhabitant hundreds if not thousands of years ago. It was first “discovered” and publicized to the outside world by Anglos (Whites) on August 14th, 1909. John Wetherill, Byron Cummings, and William Douglas were the primary leaders of the first Anglo discovery party. ¨.