Eastwatch-by-the-Sea

Eastwatch, or Eastwatch-by-the-Sea, is a castle and port located at the far eastern end of the Wall, where it drops into the Shivering Sea. Eastwatch serves as the main port for the Night's Watch.

At the time of the series, Eastwatch is commanded by Cotter Pyke.

Season 1
Lord Commander Jeor Mormont tells Jon Snow that four of Cotter Pyke's men found four wights in the snow near Eastwatch. Unlike the men at Castle Black, they had the sense to burn them.

Season 2
Tyrion Lannister takes tremendous pleasure in dumping Janos Slynt onto a boat headed for Eastwatch-by-the-Sea.

Naming
In the novels, the castle is named Eastwatch-by-the-Sea almost constantly. In the TV series, it is called 'Eastwatch' exclusively in the first season, both in dialogue and on the map on the HBO website. However, in the second season it was also called 'Eastwatch-by-the-Sea', indicating that the two terms are interchangeable.

In the books
Eastwatch-by-the-Sea serves as the main resupply post for the Night's Watch, with ships stopping there from the island of Ibben, the Free Cities far to the south and even some wildling fisherfolk are permitted to trade there. There is also some clandestine smuggling going on there, which is tolerated only as far as in that it helps the Watch.