Sections of highway in Bonneville, Jefferson and Fremont counties were closed due to weather and crashes on Saturday.
As of 7:40 p.m., U.S. Highway 20 between Ashton and the Montana state line was open. It had been closed for most of the day due to drifting and blowing snow, as well as reduced visibility.
There were also numerous accidents in the Ucon and Rigby areas on Highway 20.
In addition, the Teton Pass on Wyoming Highway 22 is reopen after a crash.
Slippery roads and black ice had prompted the U.S. Weather Service to issue a winter weather advisory for much of eastern Idaho. That advisory was canceled at noon.