The western terminus of SR 46 is at I-70 east of Terre Haute at an interchange before becoming a heavily traveled modernized 2-lane highway through Spencer where it intersects SR 67 and US 231.
The western terminus of SR 46 is at U.S. Route 40 (US 40) in central Vigo County, just east of Terre Haute. It then goes under I-70 at an interchange before becoming a heavily traveled modernized 2-lane highway through Spencer where it intersects SR 67 and US 231.