Valtellina or the Valtelline valley; (Valtellina, Veltlin, Vuclina) is a valley in the Lombardy region of northern Italy, bordering Switzerland. Today it is known for its skiing, its hot spring spas, its cheeses (in particular Bitto, named after the torrent Bitto) and its wines. In past centuries it was a key alpine pass between northern Italy and Germany and control of the Valtelline was much sought after, particularly during the Thirty Years' War.
In 1797 the growing power of the First French Republic created the Cisalpine republic in Northern Italy. On 10 October 1797, the French supported a revolt in the Valtellina against the Graubünden (the "Grey Leagues"; Grisons in French, now a Swiss Canton) and joined the Cisalpine Republic.
In the region north of Morbegno in the Costiera dei Cech live a cultural group believed to descend from an 8th century Frankish invasion of Italy.
The area was originally a mix of Romansh and Italian languages but now Italian is the dominant language.
Industrially, the area is famous as the home of the world's first mainline electrified railway. The electrification of the Valtellina line took place in 1902, using three-phase power at 3,600 V, with a maximum speed of 70 km/h. The system was designed by the brilliant Hungarian engineer Kálmán Kandó who was employed by main contractors the Budapest-based Ganz company.