Bergen County is the most populous county in the U.S. state of New Jersey.As of 2015, Bergen County's Census-estimated population was 938,506, an increase of 3.7% from the 2010 United States Census, when its population was enumerated at 905,116, which in turn represented an increase of 20,998 (2.4%) from the 884,118 counted in the 2000 Census. Located in the northeastern corner of New Jersey and its Gateway Region, Bergen County is part of the New York City Metropolitan Area and is directly across the George Washington Bridge from Manhattan.Bergen County's population resides among 70 municipalities but no large cities. Its most populous place, with 43,010 residents at the time of the 2010 census, is Hackensack, also its county seat. In 2010, Mahwah covered the largest area of any municipality, at.Bergen County is one of the wealthiest counties in the United States, with a median household income of $81,708 per the 2010 Census, increasing to an estimated $84,677 in 2014, which was almost 18% higher than the $71,919 median statewide. The county hosts an extensive park system totaling nearly.