More commonly known these days as the "Mohawk Valley", this valley follows the Mohawk River as it runs between the Catskill and Adirondack mountains. It is part of the territory of the Kanien'kehá:ka - sometimes known as the "Mohawk" in English, hence the name.
The valley also happens to be the only natural route from the Atlantic Ocean to the Great Lakes - meaning it was the only easy way to get from the coast into frontier territory, and up into Canada. This made the valley incredibly strategically important during the French and Indian War and during the Revolutionary war.
And by 'strategically important' I mean the valley was contested territory and regularly raided. Most of the settlements in it were razed during the Revolutionary War - actually, the damage to the surrounding farmland was so bad that food had to be shipped into the area from the south. The Revolution is known in the area as "The Burning of the Valleys" - that says it all, really.