Rainbow Bridge National Monument

The World’s Largest Natural Bridge

By its wondrous size, majesty, and mystery, Rainbow Bridge has inspired people throughout time. Native Americans living in the region have long held this natural bridge sacred. Since the bridge became widely known in the early 1900s, thousands of people from around the world have visited each year. to view its beauty and explore its geology. It is 290 feet from its base to the top of its arch – nearly as tall as the Statue of Liberty – and spans 275 feet across the river. The top of the arch measure 42 feet thick and 33 feet wide.

Geology and Formation

How was Rainbow Bridge formed? By water. So were other sandstone arches and alcoves elsewhere on the Colorado Plateau. Water dissolves the calcium carbonate (limestone) that cements the sandstone’s sand grains. As it freezes and expands in cracks, water breaks off slabs of rock, creating varied sculptures over millions of years.

The rock layer from which Rainbow Bridge was formed is relatively soft Navajo sandstone and shale of the Kayenta formation. Iron oxide and manganese have colored all rich rock shades of pink, red, and brown. At first, water flowing off Navajo Mountain meandered over Navajo sandstone, taking the path of least resistance to the Colorado River. Over time the channel scoured from the rock grew deeper. At the site of Rainbow Bridge the stream chanced to flow in a tight curve around a narrow fin of soft Navajo sandstone. Geology tells us that when the stream cut down to the Kayenta layer, the water began to force its way through the softer Navajo sandstone fin. Eventually the stream cut clear through the fin, and Rainbow Bridge was created. Other forces – calcium carbonate dissolving and ice wedging away chunks of rock – shaped Rainbow Bridge into a near-perfect parabola. Over time the same forces that shaped Rainbow Bridge is being played out many time over in the sunset-colored canyons of the Colorado Plateau.

Exploring Rainbow Bridge

Next morning early we started our toilsome return trip. The pony trail led under the arch. Along this the Ute drove our pack-mules, and as I followed him I noticed that the Navajo rode around outside. His creed bade him never pass under an arch…This great natural bridge, so recently "discovered" by white men, has for ages been known to the Indians. Theodore Roosevelt, after his 1913 visit, from A Book Lover’s Holiday in the Open

Tucked among the rugged, isolated canyons at the base of Navajo Mountain, Rainbow Bridge was known for centuries by Native Americans who lived in the area and used the land as indian burial grounds. Ancestral Puebloan residents were followed much later by Paiute and Navajo groups. Several Paiute and Navajo families still live nearby.

By the 1800s wandering trappers, prospectors, and cowboys had surely seen Rainbow Bridge, but it was not publicized until 1909. Two separate exploring parties, one headed by University of Utah dean Byron Cummings and another by government surveyor W.B. Douglass – began searching for the legendary span. Eventually they joined forces, led by Paiute guides Nasja Begay and Jim Mike along with trader and explorer John Wetherill. Men and horses endured heat, slickrock slopes, treacherous ledges, and sandstone mazes. In late afternoon, August 14, coming down what is now Bridge Canyon, the party saw Rainbow Bridge for the first time.

In May 1910 President William Howard Taft created Rainbow Bridge National Monument to preserve this "extraordinary natural bridge, having an arch which is in form and appearance much like a rainbow, and which…is of great scientific interest as an example of eccentric stream erosion." After the initial publicity, a few more adventurous souls journeyed to Rainbow Bridge. Zane Grey and Theodore Roosevelt were among those early travelers who would make the arduous trek from Oljeto or Navajo Mountain to the foot of the Rainbow. After World War II, surplus rubber rafts made visiting Rainbow Bridge easier, although the raft trip still required several days of floating the Colorado River plus a 7-mile hike up-canyon. By the early 1950s people could travel by jet boats from Lees Ferry, then make the hike – for a trip totaling only three days!

What Roosevelt and contemporaries saw – evidence of Rainbow Bridge’s significance to early and present-day Native Americans – is difficult to discern today. Much archeological evidence has been lost as Lake Powell, along with thousands of visitors, arrived. The Glen Canyon Dam was authorized in 1956. By 1963 the gates on the dam closed and rising Lake Powell began to engulf the river and its side canyons. Higher water made access to Rainbow Bridge much easier, bringing thousands of people to see it each year.

Navajo Indian Burial Grounds

In 1974 Navajo tribal members who lived in the vicinity of Rainbow Bridge filed suit in U.S. District Court against the Secretary of the Interior, the Commissioner of the Bureau of Reclamation, and the Director of the National Park Service. The suit sought to preserve important Navajo indian burial grounds and religious sites being inundated by the rising waters of Lake Powell. The court ruled against the Navajo, saying that the need for water storage outweighed their concerns. In 1980 the Tenth District Court of Appeals ruled that to close Rainbow Bridge, a public site, for Navajo religious ceremonies would violate the U.S. Constitution, which protects the religious freedom of all citizens.