Mountains of the Moon

The Mountains of the Moon form the western edge of the Vale of Arryn, separating that territory from the Riverlands to the west. They are a substantial mountain range with many splinter ranges that dominate most of the territories ruled by House Arryn.

In the books
In the Song of Ice and Fire novels, the Mountains of the Moon are tall and forbidding, among the tallest peaks in all of Westeros. The largest pass through the mountains is guarded by a fortress known as the Bloody Gate, whilst the Eyrie, the seat of the Arryns, is built on the sholder of the Giant's Lance, the tallest mountain in the region.

The western foothills and flanks of the mountains are home to warrior clans of varying size but unmitigated ferocity against the civilised inhabitants of the region. Due to their superior knowledge of the terrain, attempts by either the river lords or the valemen to wipe them out have failed. However, they lack the knowledge and technology needed to successfully prosecute siege warfare against the Vale of Arryn, which they regard as their true birthright.