Falls of Rauros

Anduin
Map of the river Anduin and surrounding areas
J. R. R. Tolkien's legendarium location
Other name(s)	The River, The Great River, River of Gondor, Langflood
Type	The longest river in the Third Age
Location	Between the Misty Mountains and Mirkwood flowing south and through Gondor to the Great Sea

In J. R. R. Tolkien's fictional Middle-earth, Anduin is the Sindarin name for the Great River of Wilderland, the longest river in the Third Age (the original Sindarin name means Long River). The ancestors of the Rohirrim called it Langflood. It flowed from its sources in the Grey and Misty Mountains to the Mouths of Anduin (Ethir Anduin) in the Great Sea (Belegaer). In her Atlas of Middle-earth, Karen Wynn Fonstad estimates a total length of 1,388 miles (2,233 km).

The Anduin began as two different streams near where the Misty Mountains met the Grey Mountains. These were called the Langwell and the Greylin by the Éothéod when they lived in the triangle of land formed by it. Their old capital Framsburg was built at the confluence of these streams where the Anduin proper began. The Langwell had its source in the Misty Mountains, close to Mount Gundabad and the Greylin began in the westernmost heights of the Grey Mountains.

The upper Anduin flowed parallel to the Misty Mountains in a broad vale which formed the western part of Rhovanion, lying between the mountains and Mirkwood. After passing the Carrock and Lórien, the river and mountains parted company, and the river meandered through the Brown Lands (once the home of the Entwives) via the North and South Undeeps until it flowed through into the Emyn Muil. There it negotiated the Sarn Gebir (a series of ferocious rapids), rushed past the Argonath, and entered a lake (Nen Hithoel).