The High Marches is the empire of the High Elves. Once, it spanned all of the north eastern shores of Alkyron, to the western reaches of the Great Plains, to the forest of the Greenwood. Today, it is a shadow of it's former glory.
The High Marches are known for their ambitious military conquests. There isn't a kingdom on Alkyron that hasn't felt their influence to one degree or another. Despite their current military engagements they are still a force to be reckoned with.