The Wye has been voted the public's favourite river in England and Wales.
The award has been organised by the Our Rivers campaign to celebrate the nations' rivers and highlight threats to wildlife.
The Wye - which starts in mid Wales, winds over England's border and back and runs into the Severn Estuary - was described as "magical and timeless".
The awards, backed by WWF Cymru, RSPB, Angling Trust and the Salmon and Trout Association, were launched in August.
WWF Cymru said thousands of people had cast their votes online for the rivers they love, and for those which need urgent attention.
The Wye is the fifth-longest river in the UK, running some 153 miles (246km) from its source on the slopes of Plynlimon to the Severn Estuary near Chepstow, Monmouthshire.
It winds its way through or past Rhayader, Builth Wells, Hay-on-Wye, Hereford, Ross-on-Wye, Symonds Yat, Monmouth and Tintern.
The river is a site of special scientific interest and much of the lower Wye valley is designated an area of outstanding natural beauty.
Anne Meikle, head of WWF Cymru, said the award was well deserved.
"Clearly the public appreciate the Wye's beauty, serenity and the wealth of wildlife which make the river and its banks their home," she said.
"It is a stunning river which captures the imagination of everyone who visits it."
However Ms Meikle added that despite the award, the Wye faced threats. They include high levels of pollution from agriculture, declining fish stocks and damage from excessive grazing.
"[These] problems... need to be dealt with to ensure future generations can enjoy its beauty," she said.
Dr Stephen Marsh-Smith of the Wye and Usk Foundation, a charity concerned with restoring the habitat, water quality and fisheries of the Wye, said the result of the survey was "no surprise".
"It's interesting to see why some rivers did not attract people's attention - it was all the negative things, the visible bad things that people see in them," he said.
"What the Wye has is vast lengths of unspoilt beauty."
Dr Marsh-Smith said the river was famous as a fishing river, it had a very busy canoeing section - the English stretch - and was surrounded by "wonderful" Wye Valley walks.
The Wye is famous for its salmon, and it is also home to a population of shad, one of the UK's rarest fish species, which run 120 miles (193km) up to Builth Wells to spawn.
The river is also renowned for its otters and birds, he added.
"It has everything," he said. "It has not been spoilt by industry like the Trent or the Thames.
"And a lot of people on both sides of the border know the Wye."