At Nooksack Falls, the river flows through a narrow valley and drops freely 88 feet (27 m) into a deep rocky river canyon. The falls are viewable from the forested cover near the cliff edge.
The crossing of the St. Croix River was difficult for the railway, since the original bridge across the river was very low and trains had to contend with steep grades on both sides of the river. This made it necessary to use helper engines and to make trains shorter.