From A Wiki of Ice and Fire
|Location||the Vale of Arryn, Westeros.|
|Government||House Borrell , Feudal Lord.|
|Religion||Faith of the Seven|
|Named for||Three Sisters|
|Notable places||Night Lamp, Belly of the Whale, Breakwater|
Sisterton is a town located on Sweetsister, an island of the Three Sisters, in the Bite. The seat of House Borrell and House Sunderland, it is considered the most notorious smuggler's den in all of Westeros.
Sisterton is a small, mean town, rank with the odors of pig waste and rotting fish. Its streets are made of mud and planks, while its are houses daub-and-wattle hovels roofed with straw. By the Gallows Gate there are always hanged men with their entrails dangling out. The Night Lamp, a lighthouse tower, and House Borrell's castle, Breakwater, are located at Sisterton.
Prior to becoming a smuggler's den, Sisterton was a pirate's nest.