1623: Today's New Jersey is claimed by the Dutch and known as part of New Netherlands
of Passaic County
1664: The land is claimed by the English and named New Jersey
1675: Essex County was formed in East Jersey Province, including the land of today's Passaic County
1682: Boundaries for Essex County were set
1710: A vast portion of Essex County was annexed by Bergen County. All current land of Passaic County north of the Passaic River becomes part of Bergen County. The southern portion remains in Essex. (Note map)
1769: A 50 year border dispute between New York and New Jersey is settled with the current NJ/NY boundary being set. Until this time, most of today's Passaic County north of the Passaic River was claimed by both New Jersey and New York.
1837: Passaic County was formed from portions of Bergen and Essex Counties, consisting of five townships: Acquackanonk, Manchester, Paterson, Pompton, West Milford
1907: A small tract of land in Acquackanock and Little Falls Townships is annexed by Montclair, Essex County. This tract is still visible as the notch along the otherwise straight southern border of Passaic County.