Klausen Pass, Mountain pass in Uri, Switzerland

Klausen Pass is a mountain pass in the Swiss Alps linking Altdorf in the canton of Uri with Linthal in the canton of Glarus. The paved road runs 46 kilometres between the two, climbing from Altdorf through the Schächen Valley communities of Bürglen, Spiringen and Unterschächen and descending via the Urnerboden. At the summit, in Uri, stands a concrete post carrying a white sign reading "1952 m" and "6404 ft" with "A.C.S." at the lower right, and below it a red diamond plaque with a white bicycle symbol.

The pass began as a cattle track, controlled by a customs office in Bürglen by 1196. A hospital for travellers was built at Urnerboden in 1590, with Uri and Glarus sharing upkeep of the route. Glarus sold its share to a private owner in 1625, and a chapel was built on the summit in 1717. A road from Altdorf reached Unterschächen in 1870 and was extended over the pass to Linthal between 1893 and 1899.

The Klausenpassrennen hillclimb ran from 1922 to 1934 on the pass road; Rudolf Caracciola set the record of 15m 22.2s in 1934 driving a Mercedes. Since 1993 a memorial run for vintage cars has been held, nominally every four years, most recently on 27–29 September 2013.

The road closes from October to May due to snow, with PostBus Switzerland providing service during the open season. Visitors should expect variable weather and steep switchbacks when traveling through during summer months.

The Uri–Glarus border lies about 8 km down the Linthal slope, not at the summit, which is in Uri. Legend says it was fixed in 1315 by runners starting at cockcrow from Altdorf and Linthal; Glarus fed its cock well, it overslept, and Uri's hungry bird crowed early. The Glarus runner then carried his Uri rival uphill until he collapsed, marking the spot.