Mt. Washington was first settled by Dutch pioneers who made their way east from what is now New York State, up through the Bash Bish ravine to what is now Mt. Washington as early as the late 1600s.
At that time all the land in Mt. Washington fell into Robert Livingstone’s land grant given by the Governor of New York Colony in 1686.
For most of the 18th century the border between New York and the Massachisetts Bay Colony was in dispute, with New Yorkers laying claim to land as far east as Great Barrington and the government of the Massachusetts Bay Colony believing its boundary extended, as stated in its charter, to the Pacific Ocean.
The border dispute was finally settled with the border being placed 20 miles east of the Hudson River, and thus Mt. Washington was nestled right along the border.