When English colonists organized counties in 1683 in what is now New York, the present Chenango County was part of Albany County. This was an enormous county, including the northern part of New York State as well as all of the present State of Vermont and, in theory, extending westward to the Pacific Ocean. However, territories located to the west of present-day Pennsylvania were under effective French control as part of New France. Albany County was reduced in size on July 3, 1766, by the creation of Cumberland County, and further on March 16, 1770, by the creation of Gloucester County, both containing territory now in Vermont.