Demarest is a borough in Bergen County, New Jersey, United States. As of the 2010 United States Census, the borough's population was 4,881, reflecting an increase of 36 (+0.7%) from the 4,845 counted in the 2000 Census, which had in turn increased by 45 (+0.9%) from the 4,800 counted in the 1990 Census. Located in the northeastern corner of New Jersey and its Gateway Region, Demarest is part of the New York City Metropolitan Area.
Demarest was formed by an act of the New Jersey Legislature on April 8, 1903, from portions of Harrington Township and Palisades Township. The borough was named for the Demarest family and for the Demarest train station, which had in turn been named for Ralph S. Demarest, who was a director of the Northern Railroad of New Jersey that built the station and represented the area in both the New Jersey General Assembly and the New Jersey Senate in the mid-19th century.
According to the United States Census Bureau, the borough had a total area of 2.08 square miles (5.38 km2), including 2.07 square miles (5.37 km2) of land and 0.01 square miles (0.02 km2) of water (0.34%).
At the heart of Demarest is an area known as the Duck Pond, which is a section of the Tenakill Brook.
The borough borders the Bergen County municipalities of Alpine, Closter, Cresskill, Dumont and Haworth.
The 2010 United States census counted 4,881 people, 1,597 households, and 1,404 families in the borough. The population density was 2,361.8 per square mile (911.9/km2). There were 1,659 housing units at an average density of 802.7 per square mile (309.9/km2). The racial makeup was 70.21% (3,427) White, 0.64% (31) Black or African American, 0.02% (1) Native American, 26.41% (1,289) Asian, 0.00% (0) Pacific Islander, 0.74% (36) from other races, and 1.99% (97) from two or more races. Hispanic or Latino of any race were 4.43% (216) of the population. Korean Americans accounted for 17.3% of the population.
Of the 1,597 households, 45.1% had children under the age of 18; 76.8% were married couples living together; 8.4% had a female householder with no husband present and 12.1% were non-families.