The Soča (in Slovenian) or Isonzo (in Italian) is a river that flows from north to south in the Western Slovenia and North-Eastern Italy. It originates in the Trenta valley in the Julian Alps of Slovenia at around 1100 metres of altitude. It then flows through Bovec, Kobarid, Tolmin, Nova Gorica and Gorizia (where it crosses the Slovenian-Italian border), and flows into the Adriatic Sea close to the Italian town of Monfalcone (Slovenian: Tržič). Its total length is about 140 km.
The Soča is an alpine river well known for its natural beauty and characteristic blue color. It is a habitat of an endemic species of trout, the Salmo trutta marmoratus (or the marble trout, in Slovenian: Soška postrv).