The Green Mountain Boys were a dedicated group, who managed to create a good deal of commotion while fighting for independence, both from New York and from England.
As a symbol of their cause, they created a flag. It was green, to reflect their wonderful green mountains. In the upper left hand corner, it had a blue field with thirteen white stars scattered on it to honor the thirteen united colonies, even though those thirteen colonies would not allow Vermont into their new United States of America.
Here is a picture of the Green Mountain Boys flag, as displayed at Old Constitution House in Windsor, Vermont.