Gulltown is the largest city in the Vale of Arryn, the region controlled by House Arryn of the Eyrie. The city is located east of the Eyrie and south of Runestone on the east coast of the Vale.
In the books
In the A Song of Ice and Fire novels Gulltown is under the control of House Grafton. The ports were once controlled by Lord Petyr Baelish before Lord Jon Arryn brought him to King's Landing.