Greyflood

The Greyflood River was also known as the River Hoarwell, and in the Elvish tongue, Mitheithel. Its source was in the Ettenmoors, and it flowed down to join the Loudwater River. It had only one crossing, the Last Bridge. It took Aragorn, Frodo Baggins, Meriadoc Brandybuck, Peregrin Took, and Samwise Gamgee about seven days to reach it from Weathertop. At the Last Bridge, Aragorn found a beryl, an elf-stone, set there by Glorfindel when he drove off the Black Riders who were there.