The Township of Independence was established by an act of the New Jersey State Legislature in 1782. This occurred through the division of Hardwick Township which at that time made it a section of Sussex County. Next through another act of the State Legislature in 1825 it was one of the seven large southerly townships, formerly in Sussex County, which together comprised the area that became Warren County. As the seven townships gradually were subdivided, Independence was reduced to half its original size through the loss of Hackettstown in 1853 and Allamuchy in 1873. The population thereby decreased to around one thousand, having the boundaries that it has today. It is roughly eight miles long from the northwest to the southeast corners, about six miles across its widest point and covers an area of 20.4 square miles.