N.J. Stat. Ann. § 40A:13-2

The territorial limits of each county or portion thereof fronting upon the open sea shall extend to a line parallel with the ocean shore line of the county, and distant, easterly, 3 nautical miles therefrom and the division lines between said counties shall extend from the several points where they reach the sea in courses east until they severally reach said outer lines of said counties for all purposes including jurisdiction over criminal and other offenses committed.