Una

Una National Park covers 19,800 hectares in northwestern Bosnia and Herzegovina, in the Federation entity's Una-Sana Canton. The park protects the Una River and its main tributary the Unac, along with their exceptional cascading waterfall systems, turquoise waters, and surrounding canyon landscapes. The Una River is celebrated as one of the cleanest and most scenic rivers in Europe, characterised by a succession of tufa waterfalls, emerald pools, and rapids that have made it a destination for whitewater sport and nature tourism. The park encompasses a mosaic of beech and fir forest, river meadows, dramatic karst terrain, and traditional Bosnian villages.

The Una River system is biologically exceptional, supporting some of the largest and healthiest populations of Huchen (Danube salmon) in Europe—a species of European conservation concern. Brown trout, grayling, and numerous other fish species inhabit the clear, oxygen-rich waters. Otter populations are healthy along the Una and Unac. The surrounding forests support brown bear, wolf, lynx, wild boar, red deer, and chamois. The park's rivers and wetlands are important for waterbirds including kingfisher, white-throated dipper, common sandpiper, and grey wagtail. White stork nests in villages adjacent to the park.

The park's vegetation ranges from riparian communities of white willow, white poplar, and black alder along the river banks through mixed beech-fir montane forest on the surrounding plateau to subalpine communities at higher elevations. The tufa waterfalls and cascades support specialised bryophyte communities that actively precipitate the calcium carbonate forming the tufa. Rare plant species in the park include several endemic Dinaric species. The floodplain meadows maintained by traditional haymaking are rich in wildflowers. Over 1,300 plant species are recorded for the park area.

The Una River's extraordinary visual character—turquoise colour, tufa waterfalls, and cascades—is created by the dissolution of Jurassic limestone in the river's headwaters and the subsequent precipitation of calcium carbonate (tufa) as the water flows over obstacles. The tufa formations at Martin Brod, Štrbački Buk, and Šturlić Falls are actively growing geological features, adding millimetres per year. The park's landscape is underlain by Triassic and Jurassic limestones and dolomites typical of the Dinaric system. The Una canyon downstream from Bihać cuts through Palaeozoic schists and crystalline rocks.

Una National Park's climate is transitional between continental and modified Mediterranean influences. Summers are warm and moderately dry, with river valley temperatures reaching 25-28°C—ideal conditions for water sports. Winters are cold with reliable snowfall, and the river typically does not freeze at its lower sections due to the moderating groundwater springs feeding it. Annual precipitation averages 1,000-1,400 mm, with a secondary spring maximum in addition to the main autumn-winter peak. The park's position in the Krajina region means it receives moisture from both Atlantic weather systems and Mediterranean frontal systems.

The Una valley has been settled since the Neolithic period, as evidenced by archaeological finds throughout the river corridor. Illyrian and later Roman communities used the river valley as a communication route. During the medieval Bosnian kingdom, the Una formed an important frontier zone. The Ottoman conquest in the 15th-16th centuries brought the construction of fortifications, most notably the historic old town of Bihać with its medieval tower. The region's mixed Bosniak, Croatian, and Serbian population reflects the complex history of the Una-Sana border zone. The 1992-1995 war deeply affected the communities surrounding the park.

Una National Park was established in 2008, the most recently designated national park in Bosnia and Herzegovina. Its establishment was driven primarily by the recognition of the Una River's exceptional ecological values and the desire to develop sustainable tourism as an economic alternative for the region, which experienced severe damage during the 1990s conflict. International cooperation with Croatia on the Una-Krka transboundary aquifer and river system has informed management approaches. The park's establishment helped channel significant international tourist interest in the river's scenic and sporting qualities.

Štrbački Buk waterfall (24 m), accessible by trail from Martin Brod, is considered one of the most beautiful waterfalls in Europe and the park's signature natural feature. Martin Brod village, a traditional settlement at the confluence of the Una and Unac, features Ottoman-period watermills and a charming stone bridge. Whitewater rafting and kayaking on the Una and Unac rivers—ranging from gentle family floats to expert-level rapid sections—are the primary active tourism draws. The ruined Ostrovica fortress above the Una provides views across the canyon. The old town of Bihać is the urban gateway.

The town of Bihać (adjacent to the park) provides full accommodation, restaurants, and transport connections. Within the park, accommodation is available at guesthouses in Martin Brod and other villages. Multiple rafting operators are based along the river. The park visitor centre operates in Bihać. The park is approximately 330 km from Sarajevo and 150 km from Split (Croatia). Bus services connect Bihać to Sarajevo and Zagreb. The Una's accessibility from Croatia makes it popular with Croatian and international visitors.

Water quality protection is the park's paramount conservation challenge—the Una and Unac are extraordinarily clean rivers that are highly sensitive to pollution from upstream agricultural and municipal sources. Illegal waste dumping in the river and along stream banks is a persistent problem requiring community engagement. The tufa formations are sensitive to alteration of the river's hydrological regime and water chemistry. Rafting and kayaking activity management seeks to balance economic benefits with minimising impacts on the river ecosystem, particularly on fish spawning grounds. The park works with Croatian partners on transboundary river conservation.