Haddonfield is a borough located in Camden County, in the U.S. state of New Jersey. As of the 2020 United States census, the borough's population was 12,550, an increase of 957 from the 2010 census count of 11,593, which in turn reflected a decline of 66 from the 11,659 counted in the 2000 census Haddonfield was incorporated by an act of the New Jersey Legislature on April 6, 1875, within portions of Haddon Township following a referendum on the same day.