Once exiting Kamas, the route dips southeast and continues as such until reaching Samak, where the road turns northeast briefly.

After continuing in a general southeast direction, the highway turns northeast and north and continues as such until reaching the Wyoming border south of Evanston.

[5] During the winter months the road is closed to automobiles and is used by snowmobiles.

The state legislature designated SR-150 in 1933, running east from SR-35 (now SR-32) in Kamas to the Wasatch-Cache National Forest boundary.

[6] In 1953, it was extended east and north via Mirror Lake to the Wyoming state line.