Greywater Watch

The castle stands on one of the shifting islands of the mire, and its position moves enough that no map can pin it down for certain. That is why no ravens reach it, no maester waits there to receive them, and no knights stand guard at its gates.

That same elusiveness has protected the Reeds for generations. River kings have sent troops against Greywater Watch more than once, and so have the Freys; none of those armies ever set foot inside the castle.

As the war starts pushing toward the North, Robb Stark sends word to Lord Howland Reed at Greywater Watch. He asks the men of the Neck to watch the causeway, in case Lannister forces try to cross it on their way to Winterfell.

Later, now crowned king, Robb Stark turns to Greywater Watch again: he sends Lady Maege Mormont and Galbart Glover to ask Lord Howland's help in taking Moat Cailin back from the ironborn.

Esta es la razón por la que no llegan los cuervos y no hay maestres en el castillo, así como tampoco caballeros o maestros de armas.

What it is like · Choque de Reyes, Capítulo 28, Bran.

Varios ejércitos de los Reyes de los Ríos y de los Frey trataron de conquistar Atalaya de Aguasgrises, pero ninguno pudo encontrarla.

What it is like · Tormenta de Espadas, Capítulo 24, Bran.