The eastern terminus is at Pennsylvania Route 46 south of Colegrove in Norwich Township.

PA 146 begins at an intersection with US 6 in the community of Marvindale in Hamlin Township, heading southeast on two-lane undivided Clermont Road.

The road passes farm fields before heading into forested areas.

The route crosses into Sergeant Township and becomes Red Mill Brook Road, continuing through woodland with a few patches of farms and rural homes.

PA 146 makes a turn to the northeast to remain along Red Mill Brook Road as it continues through forests.