Closter (pronounced KLO-ster) is a Borough in Bergen County, New Jersey, United States. As of the United States 2000 Census, the borough population was 8,383. Closter, settled in 1704, was formed by an Act of the New Jersey Legislature on January 1, 1904, from portions of Harrington Township. On March 29, 1904, Harrington Park was created from portions of Closter, Harrington Township and Washington Township.