The Bosna (Cyrillic: Босна) is the third longest river in Bosnia and Herzegovina, and is considered one of the country's three major internal rivers, along with the Neretva and Vrbas Rivers; the other three major rivers of Bosnia and Herzegovina are the Una River, to the northwest, the Sava River, to the north, and the Drina River, to the east. The Bosna River flows for 271 kilometers (168 miles). Its name does not have any foreign variations. In the Roman times the river was called the Bosona, and it is thought that this is probably the Illyrian origin of the name Bosna.
Its source is at the spring Vrelo Bosne, at the foothills of the Mount Igman, on the outskirts of Sarajevo. The spring is one of Bosnia and Herzegovina's chief natural landmarks and tourist attractions. From there, the Bosna River flows northwards, through the heart of Bosnia, eventually becoming a right tributary of the Sava River.
Although it does not pass through any foreign countries, the Bosna flows through a number of cantons and regions of Bosnia. From its starting point in the Sarajevo Canton, it also flows through Zenica-Doboj Canton, Doboj Region, and Posavina Canton, in that order.