Newton is a town in Sussex County, New Jersey, United States. It is the county seat of Sussex County. As of the 2000 United States Census, the town's population was 7,997, reflecting a decline of 247 (-3.0%) from the 8,244 counted in the 2000 Census, which had in turn increased by 723 (+9.6%) from the 7,521 counted in the 1990 Census.
Newton was incorporated by an act of the New Jersey Legislature on April 11, 1864, from portions of Newton Township, which was also partitioned to create Andover Township and Hampton Township, and was then dissolved. Additional land was acquired from Andover Township in 1869 and 1927, and from Fredon Township in 1920.