The San Rafael Swell

November 2, 2020

The San Rafael Swell is a large geologic feature located in south-central Utah about 16 miles west of Green River, Utah. The San Rafael Swell, measuring approximately 75 by 40 miles consists of a giant dome-shaped anticline of sandstone, shale, and limestone that was pushed up during the Paleocene Laramie Orogeny 60-40 million years ago. Since that time, infrequent but powerful flash floods have eroded the sedimentary rocks into numerous valleys, canyons, gorges, mesas, buttes and badlands.

Interstate 70 divides the Swell into northern and southern sections, and provides the only interstate access to the region. The swell lies entirely within Emery County. The northern Swell is drained mainly by the San Rafael River, while the southern Swell is drained mainly by Muddy Creek, which eventually joins the Fremont River to become Dirty Devil River northeast of Hanksville, Utah. The Dirty Devil River flows southward into the Colorado River, while the San Rafael River joins the Green River before it also flows into the Colorado. Muddy Creek cuts into the western edge of the Swell, exits at Muddy Creek Gorge, and then flows across the Blue Hills Badlands near Caineville to its confluence with the Fremont River.

Evidence of Native American cultures, including the Fremont, Paiute, and Ute, is common throughout the San Rafael Swell in the form of pictograph and petroglyph panels. Examples are the Millsite Rock Art and the Buckhorn Draw Pictograph Panel, with rock art left by the Barrier Canyon Culture and the Fremont Culture. From about 1776 to the mid-1850s the Old Spanish Trail trade route passed through (or just north of) the Swell. In the past 150 years, areas of the Swell have been used for the grazing of sheep and cattle, as well as for uranium mining. Many of the gravel roads in the interior of the swell were originally used to service the uranium mining activities. Although surrounded by the communities of Price, Green River, Hanksville, Ferron, Castle Dale, and Huntington, the Swell itself does not support permanent residents.

The Swell has been used by Hollywood filmmakers as a location setting for alien planets, including the Planet Vulcan in the 2009 film Star Trek and the alien world in Galaxy Quest.

In 2002, then-governor Mike Leavitt of Utah proposed the creation of a San Rafael Swell National Monument.[President George W. Bush, who had authority to create such a monument under the Antiquities Act, never acted on Leavitt's proposal.

The idea of federal designation of the San Rafael Swell as a National Monument resurfaced in 2010 in a Department of the Interior document.

In May 2018, US Representative John Curtis put forward a bill to make the area a National Monument, to be called "Jurassic National Monument.”

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