The River Foyle is formed when the River Finn and the River Mourne combine at Strabane in Country Tyrone in Northern Ireland. The Finn’s source is in Donegal (Republic of Ireland) and the Mourne’s source is to the northwest of Newtonstewart (Northern Ireland). The River Foyle flows into Lough Foyle at Derry.
Facts About the River Foyle
- The River Foyle is 129 km (80 miles) long.
- It is one of the fastest flowing rivers in Europe for its size.
- Some of the River Foyle’s tributaries include the River Deele (or Burn Dale), Swilly Burn, Flushtoun Burn, Burn Dennet, and Glenmoran River.
- The Craigavon Bridge (sometimes called the Blue Bridge) spans the River Foyle in Derry. It is one of Europe’s few double-decker road bridges.
- Derry’s other bridges over the River Foyle are the Foyle Bridge and Peace Bridge (opened in 2011).
- The Lifford Bridge over the Rover Foyle is a cross-border bridge linking Strabane in County Tyrone (Northern Ireland) to Lifford in County Donegal (Republic of Ireland). It is 115 metres in length, and it carries more than 15,000 vehicles each day.

- The River Foyle is one of the best salmon rivers in Ireland.
- The water clarity in the River Foyle is poor, but the water quality is very good. As a result, the River Foyle estuary is home to lots of different species of wildlife, including sole, flounder, eels, turbot, plaice, lumpsucker, smelt, sunfish, lamprey, and pipefish.
- Harbour porpoise and bottlenose dolphins sometimes make their way into the River Foyle. There have been numerous sightings of these creatures from the bridges in Derry.
- In 1977 a killer whale swam into the River Foyle and was spotted at Derry. He was nicknamed Dopey Dick. It is believed that the same whale (now named Comet and aged 58) was part of the pod of killer whales living near the Isle of Skye in 2016.
- In the Partition of Ireland in 1922, Lough Foyle was claimed by both the UK and the Republic of Ireland. Following 1998’s Good Friday Agreement, the lough is now managed jointly by the two countries.
- The wrecks of several German U-Boats (from World War Two) are located at the bottom of Lough Foyle. At the end of the war, as part of Operation Deadlight, some of the surrendered German fleet was to be scuttled. Several U-boats sank before they could be destroyed.
- Seals and otters are commonly spotted in the waters of the River Foyle at Derry.
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