The roadway is 65.6 kilometres (40.8 mi) long.

The route begins by straddling the Saskatchewan border going north, before curving eastward into Manitoba.

The route continues west as Saskatchewan Highway 361.

The road is unpaved for its first 4.5 kilometres (2.8 mi) or so before becoming paved just west of Tilston.

PR 345 traverses mainly rural areas between the Saskatchewan province line and PTH 21, while traversing the towns of Tilston, Broomhill, Bede, Bernice, and Lauder.