Bergen was a city that existed in Hudson County, New Jersey, United States, from 1855 to 1870. Bergen was originally incorporated as a town by an Act of the New Jersey Legislature on March 24, 1855, from portions of Bergen Township. In 1862, it did a reverse takeover, absorbing the remaining portions of Bergen Township. On April 14, 1863, portions o…Bergen was a city that existed in Hudson County, New Jersey, United States, from 1855 to 1870. Bergen was originally incorporated as a town by an Act of the New Jersey Legislature on March 24, 1855, from portions of Bergen Township. In 1862, it did a reverse takeover, absorbing the remaining portions of Bergen Township. On April 14, 1863, portions of the town were taken to form Greenville Township.