Eastern Road

The Eastern Road (also known as the High Road) is a major highway in the Seven Kingdoms. It begins at the Crossroads Inn where the highway intersects with the Kingsroad. From the crossroads in the northern Riverlands it continues on into the Vale of Arryn.

Loosely speaking the Eastern Road is essentially a continuation of the River Road, and together they form a major highway for east-west travel across the continent, from the Vale in the east all the way to Lannisport in the Westerlands, passing Riverrun in between. However, the name of the highway changes when it passes the Kingsroad so that the two halves are considered two separate roads, probably due to their drastically different topography (wide and wet river paths versus treacherous and narrow mountain paths).

From the Crossroads Inn, the Eastern Road only runs a short distance east through the northern Riverlands before it enters the Vale of Arryn. The road leads from the crossroads to the only major pass through the Mountains of the Moon that form the Vale's border. The road is very dangerous in the mountain crossing, weaving its way through rocky narrow turns, and travelers are often assaulted by barbarous Hill tribes and prowling Shadowcats.

Eventually the mountain pass comes to a narrow choke point which forms the only way through the mountains, guarded by a strategically vital fortress known as the Bloody Gate. After passing through this fortress the road enters the Vale proper, and travelers are much better protected from dangers. Soon after passing through the Bloody Gate, the road arrives at The Eyrie, the ruling seat of House Arryn. The road then continues on to Gulltown, the main port of the Vale and fourth largest city in Westeros.

In the books
In the Song of Ice and Fire novels the Eastern Road is much the same. The TV series largely omitted the appearance of the Bloody Gate, instead having Catelyn Stark's company encounter a patrol from the fortress led by Ser Vardis Egan.