Chester Borough is a borough in southwestern Morris County, in the U.S. state of New Jersey. As of the 2020 United States census, the borough's population was 1,681, an increase of 32 from the 2010 census count of 1,649, which in turn reflected an increase of 14 from the 1,635 counted in the 2000 census. Chester's name is derived from the township, which was named for Chestershire in England.