The Eisack (German: Eisack, pronounced[ˈaɪzak]ⓘ; Italian: Isarco[iˈzarko]; Latin: Isarus or Isarcus) is a river in Northern Italy, the second largest river in South Tyrol. Its source is near the Brenner Pass, at an altitude of about 1990 m above sea level. The river draws water from an area of about 4,200 km2. After about 96 km, it joins the Adige river south of Bolzano. At first the river flows through the Wipptal and after the village of Vahrn through the Eisacktal. Its source is sung of in the Bozner Bergsteigerlied as the northern frontier of the South Tyrolean homeland.