The Greymane Wall before its destruction.
The Greymane Wall was erected after the Second War, by Genn Greymane, as the Kingdom of Gilneas isolated itself from the Alliance due to a dispute surrounding the internment camps for the orcs. It is a large wall spanning from the mountains to the shore, located at the southern edge of the Silverpine Forest (near Pyrewood Village) and the northern edge of Gilneas, a region formerly known as Arevass. The Wall itself began construction the same year as the Second War ended, though it did not complete construction until 1135 F.A.. During this time, a strong border patrol was established to stand in for the wall, resulting in leaving or entering Gilneas near impossible.
This enormous gray wall marks the boundary between Gilneas and Lordaeron. It once kept the lands of Gilneas safe from invaders, but was destroyed following the second shattering. Those on the other side in Gilneas have been spared from the Plague, though the worgen curse has taken effect instead.
The controversial Greymane Wall sowed civil discord in Gilneas, eventually leading to the Northgate Rebellion, a devastating civil war that nearly destroyed the kingdom.
The Greymane Wall, following the Shattering.
Though Genn Greymane was able to put down the dissenters with the apprehension of the rebellion's leader, Darius Crowley, the kingdom began to experience other troubles in the form of the Worgen and later the Forsaken.