Highway 20 begins at Alsike along Highway 39 and proceeds 10 km (6.2 mi) south to Breton where it crosses Highway 616. It continues south another 17 km to Winfield where it crosses Highway 13. From Winfield the highway continues south for another 15 km to Hoadley where Highway 611 branches off to the east. 12 km further south it goes through Bluffton where Highway 607 branches off to the west.
Highway 53 branches off Highway 20 to the east towards Ponoka about 10 km south of Bluffton. The highway then travels 2 km before meeting Highway 20A, which proceeds into Rimbey. Highway 20 turns left and proceeds another 3 km before Highway 53 branches off to the west through Rimbey to Highway 22. The highway proceeds southeast for 22 km where Highway 771 branches off to the north. The highway meets Highway 12 just east of Bentley 2 km later.