July 1st, 1676 (Old Style) was the date when the English land between the Hudson and Delaware rivers was divided into two colonies. There had been specific land grants, including one to a Mr. Fenwick, but control and governance was not clear so:
“…Quakers William Penn, Gawen Lawrie, Nicholas Lucas and Byllynge became the owners of the rest.’ Since they wished to develop a Quaker colony in ‘Nest Jersey, needed to establish title in view of the Duke‘s failure to recognize Fenwick’s holdings, and wished control of the Delaware River rather than southern Jersey as left by the 1674 boundary, the four latter Quakers arranged to Sign a “Quintipartite Deed” with George Carteret on July l, 1676 to divide New Jersey into East and West Jersey.”*
* According to “The Story of New Jersey’s Civil Boundaries, 1606-1968.”, by John P. Snyder First Edition, Bureau of Geology and Topography
Trenton, New Jersey 1969
Reprinted by New Jersey Geological Survey 2004
I believe that we could also celebrate on July 12th, using the New Style calendar.
Link: https://dspace.njstatelib.org/items/72166dee-16ab-4c5e-bdb3-84c4b0fab662