Great St Bernard Pass

The Great St Bernard Pass (French: Col du Grand St-Bernard, Italian: Colle del Gran San Bernardo, German: Grosser Sankt Bernhard; Romansh: Pass del Grond Son Bernard) is the third highest road pass in Switzerland, at an elevation of 2,469 m (8,100 ft). It connects Martigny in the canton of Valais in Switzerland with Aosta in the region Aosta Valley in Italy. It is the lowest pass lying on the ridge between the two highest mountains of the Alps, Mont Blanc and Monte Rosa. It is located on the main watershed that separates the basin of the Rhône from that of the Po.

Great St Bernard is one of the most ancient passes through the Western Alps, with evidence of use as far back as the Bronze Age and surviving traces of a Roman road. In 1800, Napoleon's army used the pass to enter Italy, an event depicted in Jacques-Louis David's Napoleon at the Saint-Bernard Pass and Paul Delaroche's Bonaparte Crossing the Alps, both notable oil paintings. Having been bypassed by easier and more practical routes, particularly the Great St Bernard Tunnel, a road tunnel which opened in 1964, its value today is mainly historical and recreational.

Straddling the highest point of the road, the Great St Bernard Hospice was founded in 1049. The hospice later became famous for its use of St. Bernard dogs in rescue operations. The Italian side of the area includes several facilities as well. Between them is the small Great St Bernard Lake.

The Great St Bernard Pass is located near the western end of the Valais Alps, the next pass to the west, Col Ferret, marking the transition with the Mont Blanc massif. In that area, between Mont Dolent and Mont Vélan, the main crest of the Alps barely reaches 3,000 metres, unlike in the much higher section of the Valais Alps east of Mont Vélan and Grand Combin. Therefore, the Great St Bernard Pass is one of the only two road axis connecting Valais with northern Italy, the other axis being the Simplon Pass.

The pass runs northwest–southeast through the Valais Alps (formerly known as the Pennine Alps after the Roman name for the pass, poeninus mons or summus poeninus) at a maximum elevation of 2,469 m (8,100 ft). The road running through the pass, highway E27 in both Italy and Switzerland, joins Martigny on the upper Rhône in the canton of Valais, Switzerland, to Aosta in the Aosta Valley region of Italy. From Martigny Route 9 descends to Lausanne and from Aosta Route A5 descends to Torino.

From the north, in Switzerland, the route to the pass follows the lower part of the river Drance above Martigny, then into the sparsely populated Val d'Entremont (lit.: "valley between mountain") through which the Drance d'Entremont flows. After having passed the last inhabited locality, Bourg-Saint-Pierre, the road runs above a large reservoir, the Lac des Toules. At the location of Bourg-Saint-Bernard, the Great St Bernard Tunnel (and the main road) plunges through the mountains at a 1,915 m (6,283 ft) level, reducing, since the tunnel's opening in 1964, the commercial relevance of the road over the pass. The summit section of the road consists of hairpin turns before it reaches the top of the pass, after having passed the Combe des Morts.

On the south side the route descends a few metres and reaches the shores of the lake before its enters Italy. Then the route follows the steep slopes of the upper part of the torrent du Grand Saint-Bernard to the south, then turns to the east and follows the river in a bend to the south, where the mountain river enters the torrent Artanavaz near Saint-Rhémy-en-Bosses and turns to the east again, then smoothly to the southeast at La Clusaz (Gignod). Here the river enters the Buthier river in the lower end of the Valpelline valley and turns south again on which end finally the river flows into the Dora Baltea near the Pont de Pierre in Aosta. The route here in the main valley of the Val d'Aoste becomes part of the A5 motorway connecting the Mont Blanc Tunnel to the west and the upper Po Basin to the southeast.

A reduction of utility began after the construction of the Simplon Tunnel, strictly a railway tunnel, 100 km (62 mi) to the east in 1905. The much smaller historic road winding over the pass itself, which lies a few hundred metres from the Swiss border with Italy, is only passable June to September.