The Una is a river emerging in Croatia and after 4 km flow into and through the western part of Bosnia and Herzegovina for the rest of its course. On few places in its middle course and along the most of its lower course the Una forms the border between Bosnia and Herzegovina and Croatia. The river has length of 207 km and watershed area of 10,400 km², with approximately 1.000.000 inhabitants in this area basin. The region around the Una is inhabited by over a million people. The Una is a right tributary of the Sava river.

Legend has it that the river that springs in Croatia from a forceful well under a cliffs one hundred meters high, at the very border of Lika, Dalmatia and Bosnia in the small village of Suvaja, received the name Una from the initial Roman numeral uno, or first, unique or perhaps even only. For anyone who has ever visited this river, these tales are not unfounded. The spring itself is a phenomenon, as dive assessments have measured to a vertical depth of 200 m, with no bottom in site.

Una at Bosanska Krupa

The Una spring, also known as Vrelo Une, is located at the north-eastern slopes of the Stražbenica mountain in Croatia, and flows through towns and villages of Martin Brod, Kulen Vakuf, Ripac, Bihać, Bosanska Krupa, Bosanska Otoka, Bosanski Novi (Novi Grad), Kostajnica, and Dubica. It flows into the river Sava near small town of Jasenovac. The main tributaries are the Unac, the Sana, the Klokot and the Krušnica.

Over 170 types of medicinal herbs grow by the Una River; a rare plant called Campanula unensis, the Una Blue-Bell, was named after the Una river's bright turquoise and green colors. 28 kinds of fish live in this river and the biggest of which is the huchen (mladica, scientific name: Hucho hucho).

The locals of Una towns and cities claim that it is the purest river in the world. However, no statistical data is available to prove this myth. The origin of the name also has a legend connected to it; when the ancient Romans first came across this river they proclaimed "Una Unica Est" meaning Una the Unique because of the unique beauty of the river.

Una rafting

There is also an annual event held on the river Una Regata where people would go down the river in boats an kayaks from Kulen Vakuf to Vrelo Une in Croatia, with the climax in Bihac. The Regata is a sort of celebration for the river itself, rather than a boat race.

Una river