Sarn Gebir

The treacherous rapids of the River Anduin, with a name derived from the Elvish for 'stone spikes', referring to the sharp and dangerous rocks at their northern end. They appeared in the river's channel as it flowed south towards the hills of the Emyn Muil. Though the rapids ran for only about a mile, they were dangerous enough to block all river traffic, and it was said that none had survived the passage by water. For traders and other boatmen to pass this stretch of the river, a portage-way - a path along which light boats could be hauled - led alongside the river's western bank to a small natural bay at the southern end of Sarn Gebir.

From the rapids southwards the River Anduin became difficult to cross at any point: falls, marshes, and fortifications obstructed anyone travelling from one side to the other, especially in secret. For that reason, the northern limit of the rapids marked a strategic crossing-point, and though the Gondorians never claimed the lands of this region, in the time of Narmacil I they raised forts along the Anduin above the rapids to guard against invaders.

By the time of the War of the Ring, these forts were abandoned and decayed, but the northern limits of Sarn Gebir remained useful to those crossing the river. It was here that Aragorn brought the captured Gollum from one side to the other, and later the Black Riders passed this way in their search for the Ringbearer. It's notable that the Fellowship encountered a force of Orcs at exactly this point, massing at the last crossing of the Anduin before the rapids.