The North Stair was an ancient stair cut by the Gondorians in the days of the great kings of Gondor on the eastern side of the Falls of Rauros that went up from the Nindalf to the Emyn Muil to carry boats between the lake of Nen Hithoel and Rauros-foot, the basin at the foot of the Falls of Rauros.
When the Fellowship of the Ring was camped above Sarn Gebir, Boromir objected to traveling across the lake, pretending that there was no way down past the falls. Aragorn sternly reminded him of the stairway and the possibility of carrying their boats to the lower river. Later, when the Company was awaiting Frodo's decision at Parth Galen, Aragorn spoke to the others about the great works of Gondor in the area, including the great Stair beside the falls of Rauros.