In 1777 Vermont comprised of two counties. The western side of the state was called Bennington County and the East was called Cumberland County.
In 1781 Rutland was formed from Bennington County. Cumberland County was divided in Orange County, Windham County and Windsor County. Washington County (old) was formed in territory that is now in New Hampshire.
In 1782 Vermont abandoned claims to adjacent areas. Washington County (old) is abolished.
In 1785 Addison County was split off of Rutland County.
In 1787 Chittenden County was formed from Addison County.
In 1792 Franklin County was split off of Chittenden County. Caledonia County and Essex County were formed from part of Orange County. Orleans County are formed from parts of Chittenden County and Orange County.
In 1802 Grand Isle County was formed from parts of Chittenden County and Franklin County.
In 1810 Jefferson County are formed from parts of Caledonia County, Chittenden County, and Orange County.
In 1814 Jefferson County is renamed Washington County.
In 1835 Lamoille County was created from parts of Chittenden County, Franklin County, Orleans County and Washington County.
Essex, Orleans, and Caledonia counties are commonly referred to as the Northeast Kingdom.