The Tanaro (Italian pronunciation: [ˈtaːnaro]), known as Tanarus in ancient times and Tane or Tani in piedmontese language, is a 276-kilometre (171 mi) long river in northwestern Italy.It begins in the Ligurian Alps, near the border with France, and is the most significant right-side tributary to the Po in terms of length, size of drainage basin (partly Alpine, partly Apennine), and discharge.