Washington Township is a township in Bergen County, in the U.S. state of New Jersey. As of the 2020 United States census, the township's population was 9,285,
History
thumb|Seven Chimneys, built 1745–1750, is the oldest house in Washington Township and third oldest in Bergen County. Seven Chimneys was used as a stop for the Underground Railroad.|left
The Lenape Native Americans first inhabited the township and many names throughout the general area were passed down from the Lenape. Pascack and Kinderkamack are just two of these names. However, after Dutch and other European settlers began arriving in the 16th and 17th centuries, the Lenape population was decimated. It is estimated that by 1750, 90% of the Lenape population in and around present-day New Jersey was killed by European settlement through war and European diseases.
Washington Township was created by an act of the New Jersey Legislature on April 13, 1840, from the territories between the Hackensack River and Saddle River that had been part of Harrington Township. At the time of its creation, the township encompassed an area of 19,525 acre, more than . The township was named for George Washington, one of more than ten communities statewide named for the first president. It is one of five municipalities in the state of New Jersey with the name "Washington Township". Another municipality, Washington Borough, is completely surrounded by Washington Township, Warren County.
Growth in the area exploded after the Civil War with the completion of the New Jersey and New York Railway through the Pascack Valley, as communities were established near the railroad's stations. Hillsdale Township (now a borough) was created on March 25, 1898. Etna Borough, which ultimately became Emerson, was formed on April 8, 1903. River Vale (part) was the last to leave when it was created on April 30, 1906. The departures have taken the township from over to its current size. ZIP Code 07676 for Township of Washington was established effective July 2000.
Geography
According to the United States Census Bureau, the township had a total area of , including of land and of water (1.67%).
Located within the Pascack Valley of north-central Bergen County, elevations rise gradually in an east to west/south to north trajectory, and range anywhere from or less in the wooded swamplands behind Westwood Regional High School to approximately just west of Van Emburgh Avenue. Three hills are in the township: at the border of Westwood, west of Pascack Road, and another located west of Van Emburgh Avenue. Being higher in elevation, it is slightly cooler and less prone to flooding than the rest of the valley and other parts of northwestern Bergen County.
The southern end of the township bordering Emerson and Paramus is wooded wetlands at the convergence of Musquapsink Brook and three cemeteries, and has consistently the densest overnight and morning fog in the area.
As of 2026, the township is a member of Local Leaders for Responsible Planning in order to address the township's Mount Laurel doctrine-based housing obligations.