Henness Pass is named for Patrick Henness, who is credited with developing the route in 1849 or 1850 as an alternative to Donner Pass. In 1855 the road was officially surveyed by D.B. Scott when the California Legislature passed An Act to Construct a Wagon Road over the Sierra Nevada range, but a route through El Dorado County approximating the current path of U.S. Route 50 was ultimately chosen.