The line passes through the metropolitan area to the north-west of Milan, across the plain towards Gallarate. It continues through the forests of lower Varese Province towards Lake Maggiore. After Sesto Calende it crosses the Ticino River on an iron bridge, which was opened to traffic in 1882. State road 33 (the Milan-Simplon Pass road) uses the same bridge, above the railway. From Arona, the line largely runs along the western shore of Lake Maggiore, keeping above the shore, passing through the major tourist town of Stresa. After Baveno, it enters the Toce plain and runs for about up the Ossola valley to Domodossola. It then approaches the Simplon Tunnel through nine tunnels including the Varzo Tunnel, which is built as a spiral in order to gain height.