There are 21 counties in New Jersey. In 2019, Bergen County is New Jersey's most populous county with 936,692 residents. The county has no large cities and has grown by 3.35% since the 2010 census. New Jersey has nine counties with more than 500,000 residents. Other large counties in New Jersey include Middlesex County (829,685), Essex County (799,767) home to the city of Newark, Hudson County (676,061), Monmouth County (621,354), and Ocean County (601,651). Of these counties, only Monmouth County experienced a decline in population. The most rapid growth occurred in Hudson County, which grew by 6.36% since the census.
New Jersey has only two counties below 100,000 residents. The least populous county in New Jersey is Salem County with 62,607 residents, a decline of 5.11% from the census. The next-smallest county is Cape May County with 92,560 residents with a population growth of -4.79%. Of the 12 New Jersey counties with a population below 500,000, all but four experienced a decline in population.
Hudson County, New Jersey experienced the most rapid growth in the state, climbing to 676,061 in 2019 and up 6.36% from the census. Other counties that have reported rapid growth in New Jersey include Ocean County (4.17%), Union County (3.83%), and Bergen County (3.35%).