The Soča (in Slovenian) or Isonzo (in Italian) or Lusinç (in Friulian) or Sontig (in old German; Latin Aesontius or Sontius) is a 140 km long river that flows through western Slovenia and north-eastern Italy. An Alpine river in character, its source lies in the Trenta Valley in the Julian Alps of Slovenia, at around 1,100 metres above sea level. The river runs past Slovenia's highest peak, Triglav (2,864 m) before heading south past the towns of Bovec, Kobarid, Tolmin, Kanal ob Soči, Nova Gorica (where it is crossed by the Solkan Bridge) and Gorizia, entering the Adriatic Sea close to the Italian town of Monfalcone.
The Soča Valley was the stage of major military operations including twelve battles on the Italian front in World War I between May 1915 and November 1917, in which over 300,000 Austro-Hungarian and Italian soldiers lost their lives.
Due to its emerald green water, the river is also known under the name "The Emerald Beauty". It is said to be one of the rare rivers in the world that retain such a colour throughout their length. The Soča inspired the poet Simon Gregorčič to write his best-known poem Soči (To the Soča), one of the masterpieces of Slovene poetry.
The Soča is also well known for its unique trout species Salmo marmoratus (known as the marble trout), which lives in the upper course of the crystal-clear river. This species is endangered due to the introduction of other non-indigenous trout species sometime between World War I and World War II.
This region served as a film location for the 2008 Disney film Chronicles of Narnia: Prince Caspian.
