The Ziller Valley branches off the Inn Valley about 40 km east of Innsbruck, near Jenbach. It takes its name from the River Ziller, which runs through it from south to north and flows into the Inn at Strass in Zillertal. Strictly speaking, the valley stretches from Strass to Mayrhofen. It is the widest of the southern tributary valleys of the Inn and, unlike other tributary valleys, is relatively flat with a very small difference in elevation and no valley step. The difference in elevation from the mouth of the Ziller at Strass im Zillertal to Mayrhofen is only 100 m over a distance of 32 km. The character of the valley is therefore similar to that of the Inn Valley. As far as Mayrhofen, the valley floor has numerous alluvial cones caused by side streams. The villages developed on these alluvial cones, as they were spared from the regular flooding of the Ziller due to their slightly elevated position. Until the middle of the last century, half of the valley floor was marshy. Only with the regulation of the Ziller and the construction of the reservoirs, most of the valley was drained and reclaimed