Fire crews made good progress on Wednesday and increased containment on the Mile Marker 14 Fire, north of Boise, to 50%.
Fire activity continued to burn in small pockets of grass, sage and timber near Aldape Summit and north towards the high bridge on Highway 21.
So far, the fire has consumed at least 4,446 acres.
Four additional hotshot crews arrived on Wednesday.
Rocky Canyon road, Highland Valley road and all trails east to Highway 21 from Rocky Canyon are currently closed except for fire traffic.
The public is encouraged to use caution if you have to travel on Highway 21 as fire crews will be working in the area.