The River Eden is a river in Cumbria, England that flows through Carlisle on its way into the Solway Firth.

Rising to the south of Kirkby Stephen in the fells that connect the Lake District to the Pennines, its steep-sided valley soon opens out as it follows the vale past Appleby-in-Westmorland. It receives the water of many Pennine becks flowing off the Pennines to the east and longer rivers from the Lakes off to the west, including the River Lyvennet, River Leith and River Eamont which arrives via Ullswater and Penrith.

Continuing north, it passes the ancient stone Long Meg and Her Daughters and the sparsely populated beef and dairy farming regions of the vale of Cumbria. After flowing through Wetheral it merges with the River Irthing from the east, followed by the River Petteril and River Caldew from the south as it winds slowly through Carlisle. Its junction with the Caldew in north Carlisle marks the point where Hadrian's Wall crosses the river only five miles before both reach their end at the tidal flats. It enters the Solway Firth near the mouth of the River Esk after a total distance of 90 miles (145 km).

The river was known to the Romans as the Ituna.