At a length of 164.5 kilometres (102.2 mi), it is among the longer provincial roads in Manitoba.

PR 256 begins as a gravel road at PTH 41 near McAuley and winds its way south, staying within 16 kilometres (10 mi) of the Saskatchewan border.

After it crosses the Trans-Canada Highway at Elkhorn, PR 256 becomes a paved, two-lane highway and continues south to the Lyleton Port of Entry at the Antler–Lyleton Border Crossing on the Canada–United States border, located south of Pierson, in the extreme southwest corner of Manitoba.

[2] In 2014, the Canada Border Services Agency moved into a new state-of-the-art facility at Lyleton, which is the most westerly Port of Entry into Manitoba, located only three miles from the Saskatchewan boundary.

[1][4] Prior to 1992, PR 445 continued west a further 9.9 kilometres (6.2 mi) past PR 256 along a gravel section of Road 18N to the Saskatchewan border, where it continued for a short distance as Township Road 40 to come to an end at an intersection with Saskatchewan Highway 600 (Hwy 600) between Fertile and Gainsborough.