Watchung is a borough in Somerset County, New Jersey, United States. As of the 2010 United States Census, the borough's population was 5,801, reflecting an increase of 188 (+3.3%) from the 5,613 counted in the 2000 Census, which had in turn increased by 503 (+9.8%) from the 5,110 counted in the 1990 Census.
The name "Watchung" comes from the Lenni Lenape Native Americans, meaning "high hills" or from "watschu", meaning "hill".
George Washington surveyed the British troops in Perth Amboy, many miles away, from the first ridge of the Watchung Mountains. The eastern edge of these ridges reaches to the Oranges in the direction of Newark. The name "Washingtonville" was used in early times, but was rejected as the name for the area by the United States Postal Service, which felt that the state already had too many places named Washington.
Watchung, in the 1900s was a semi-rural small community of about 3,200 people in comparison with the relatively larger and more urban communities of Plainfield and Somerville. The first mayor of the town was Henry Baldwin Macdonald, who served from 1926 to 1928. Even as late as the 1960s, it was common for residents to know one another by name, with few moving in or out of the town. The 1967 Plainfield riots, however, caused an exodus of the large upper-middle class population from the nearby cities to the Watchung Hills area to communities such as Watchung, Warren Township and Bridgewater Township.
Watchung was incorporated as a borough by an act of the New Jersey Legislature on May 23, 1926, from portions of North Plainfield Township (now Green Brook Township) based on the results of a referendum held on April 20, 1926.
Fishing is allowed at Watchung Lake on a catch-and-release basis only.
In the wake of public fear that ensued after the 1938 radio broadcast of Orson Welles' The War of the Worlds, National Guard troops were stationed around the hills in Watchung, as told on the vinyl record recording of news reports of the day.
Notable figures who have lived in Watchung include Bobby Thomson, Billy Ard and Carl Banks.