The mainline began at Saint Paul, Minnesota, heading west along the Mississippi River bluffs, crossing the river to Minneapolis on a massive multi-piered stone arch bridge just below the Saint Anthony Falls. The bridge ceased to be used as a railroad bridge in 1978 and is now used as a pedestrian river crossing with excellent views of the falls and of the lock system. The mainline headed northwest from the Twin Cities, across North Dakota and eastern Montana. The line then crossed the Rocky Mountains at Marias Pass. It then followed the Flathead River and then Kootenai River to Bonners Ferry, Idaho, south to Sandpoint, Idaho, west to Newport, Washington, and then to Spokane, Washington. The extensive railroad facility of Hillyard, Washington was built along the line. From there the mainline crossed the Cascade Mountains through the Cascade Tunnel under Stevens Pass, reaching Seattle, Washington, in 1893, with the driving of the last spike at Scenic, Washington, on January 6, 1893.