The River Eden is a river in Fife in Scotland, and is one of Fife's two principal rivers, along with the Leven. It is nearly 30 miles (48 kilometres) long and has a fall of around 90 metres (300 feet). It flows from Burnside, near the border with Perth & Kinross, then slowly across the Howe of Fife (until drained in the 18th and 19th centuries a flat and waterlogged basin) and through the market town of Cupar to Guardbridge, where it enters the North Sea via the Eden Estuary, an important conservation area for wading birds and a nature reserve.