The Rainy Lake Trail is a paved, multi-use trail that connects Voyageurs National Park with International Falls, considered the icebox of the nation and the starting point of the Arrowhead 135. The trail follows the southern shoreline of Rainy River and Rainy Lake, going through woodlands, marshlands and lakefront neighborhoods. The Rainy River separates Minnesota and Ontario.

The route starts by the source of the River Bann in the lay-by of Deer's Meadow in the Mourne Mountains.  The route heads in a northerly direction, following the roads closest to the River Bann, spanning almost the entire length of the country of Northern Ireland.

The river is the longest in Northern Ireland and flows through the largest lake in the British Isles.

The first section of the route descends steeply out of the picturesque Mountains of Mourne and towards beautiful countryside of Down and Armagh and heads through the towns of Banbridge and Portadown.