The River Gweebarra (Abhainn Ghaoth Beara in Irish) runs approximately 32 kilometres through the unspoiled countryside of west County Donegal, flowing southwest from Lough Barra through a valley between the Derryveagh Mountains and the Glendowan Mountains before widening and emptying into Gweebarra Bay and ultimately the Atlantic Ocean. The river is crossed by the R252 near Doocharry and by the N56 just south of Lettermacaward, both of which offer access points. The N56 viewpoint between Ardara and Dungloe provides free parking and a panoramic view of the river's outfall into the bay.

Irish Whitewater rates the upper river section at Grade 3–5 over approximately 10 kilometres, with at least one documented Grade 4/5 rapid. A video from February 2009 shows this rapid being run by a kayaker, indicating the upper river is a serious whitewater environment suited to experienced paddlers. The lower river and estuary offer a markedly different character, with the 9-mile tidal estuary providing calmer water suitable for kayaking, canoeing, and stand-up paddleboarding. Tidal planning is important in the estuary; the Irish Marine Forecast is recommended for timing passages, particularly around Inishkeel Island, which is only accessible on foot at low tide.

The surrounding landscape includes the Lough Barra Bog Nature Reserve, a lowland blanket bog that supports Greenland White-fronted Geese, merlin, and golden plover. The estuary hosts sand goby, flounder, plaice, and turbot, while oystercatchers and curlews frequent the tidal flats. The river itself is well known for brown trout, salmon, and sea trout, with grilse arriving in June and larger salmon from August.

Atlantic weather conditions in this part of Donegal can change rapidly, and paddlers should carry appropriate gear and maintain awareness of local forecasts. The river is an active salmon and trout fishery with a formal permit system and designated beats; paddlers sharing the water with anglers should be aware of this activity, particularly during the fishing season from 1 April to 30 September.