Around the Mattmark reservoir

Start at the Mattmark dam, at about 2,200 m at the head of the Saastal. Valais Promotion calls the dam the largest earth-fill dam in Europe. A track follows the west shore of the reservoir south to its far end and the loop returns along the east shore to the dam. Valais Promotion's route text mentions two tunnels on the west shore; the second is unlit and can be bypassed on its left.

It is 8.1 km round with 45 m of ascent; allow about 2¼ hours. The grade is Easy: Valais Promotion gives 8.04 km, 2 h 15 and 46 m of ascent, and lists June to October as the best season.

Valais Promotion asks walkers to heed warning signs on river banks and along watercourses below dams and reservoirs: the water level can rise quickly and without warning. On 30 August 1965 part of the Allalin glacier broke off above the building site of the dam; 88 construction workers died.

The Saas-Fee/Saastal tourist office says the PostBus runs to Mattmark from 13 June to 25 October 2026 and gives no dates after that. It lists the parking charges for Mattmark, from CHF 1 for one hour up to CHF 5 for 4 to 24 hours. Its German page has a 'Saisonzeiten, Frühling - Herbst' section that says the road to Mattmark opens on Friday 29 May 2026 at 17:00; it gives no closing date, so check the road conditions before you go. Valais Promotion lists a restaurant on the dam crest; the tourist office gives its hours from 13 June 2026 and no closing date.

Route drawn by Global Adventurer along OpenStreetMap paths (© OpenStreetMap contributors, ODbL), with figures worked out from it. Check the forecast and the ground on the day: paths change.