Spiral Jetty is an earthwork sculpture constructed in April 1970 that is considered to be the most important work of American sculptor Robert Smithson. Smithson documented the construction of the sculpture in a 32-minute color film also titled Spiral Jetty. Built on the northeastern shore of the Great Salt Lake near Rozel Point in Utah entirely of mud, salt crystals, and basalt rocks, Spiral Jetty forms a 1,500-foot-long (460 m), 15-foot-wide (4.6 m) counterclockwise coil jutting from the shore of the lake.

In 1999, the artwork was donated to the Dia Art Foundation; it is one of 12 locations and sites owned by the foundation. Since its initial construction, those interested in its fate have dealt with questions of proposed changes in land use in the area surrounding the sculpture. In order to preserve the work, Dia asks that visitors not take existing rocks from the artwork, make fire pits, or trample vegetation. There are no facilities at the site, so visitors must carry any waste away with them.