Present-day New Jersey can trace its British settlement roots to June 24, 1664, when James, the Duke of York, made land grants to John Lord Berkeley and Sir George Carteret, that stretched from the Hudson River to the Delaware River. In the Charter for these land grants, the area was referred to as "New Jersey" in honor of Carteret's actions in the defense of the island of Jersey in the English Channel during the English Civil War.
In 1959, as the 300th Anniversary of New Jersey's founding loomed, efforts were begun to mark the Tercentenary milestone; the State's representatives in Congress began "working the halls" to secure Federal-level cooperation for potential plans. One potential plan involved a US Mint commemorative coin.
The Camden County Coin Club (New Jersey) drafted and sent letters to United States ("US") Senators Clifford Philip Case (R-NJ) and Harrison Williams (D-NJ), as well as to William Thomas Cahill (R-NJ) in the House of Representatives ("House"). The letters sought the striking of a half dollar to commemorate the 300th Anniversary of New Jersey.
Note: The Westchester County (New York) Coin Club ("WCCC") was the catalyst behind the 1938 New Rochelle, NY 250th Anniversary Half Dollar (see: 1938 New Rochelle NY 250th Anniversary, in 1959, the Camden County Coin Club (New Jersey) ("CCCC") looked to follow the path previously traveled by the WCCC.The coin effort stalled, however, as there is no evidence that a commemorative coin bill for New Jersey's 300th Anniversary was ever introduced in Congress. Multiple private medals were struck, however, here's the Official medal of the State of New Jersey Tercentenary Commission that was struck by the Medallic Art Company ("MACO"):
New Jersey Tercentenary Medal - Silver

(Look for a full post on the New Jersey medal in the near future.)
For other of my posts about commemorative coins and medals, including more about Phantom coin proposals, see:
Commems Collection