"In July 1777 delegates from 28 towns met and declared independence from jurisdictions and land claims of British colonies in New Hampshire and New York. They also abolished slavery within their boundaries."
First state to outlaw slavery...sorta. Massachusetts de facto outlawed slavery by a court decision in 1781 http://en.wikipedia.org/wiki/History_of_slavery_in_Massachus... , before peace was settled with the British in the Revolutionary War, and it was one of the original 13 states. Vermont was the first state to join the union after the original 13.
In 1777 the British controlled Manhattan and Long Island, with the Americans controlling the upper Hudson, and it stayed that way for the rest of the war. So politically New York must have been in turmoil, easing the way for Vermont's secession.
"In July 1777 delegates from 28 towns met and declared independence from jurisdictions and land claims of British colonies in New Hampshire and New York. They also abolished slavery within their boundaries."
http://en.wikipedia.org/wiki/Vermont_Republic