Vailsburg is an unincorporated community and neighborhood within the city of Newark in Essex County, New Jersey, United States. Part of the West Ward, its elevation is 280 ft. As of 2000[update], Vailsburg had a population of 34,348. The Vailsburg section of Newark is on a hill which closely aligns with the suburban and park areas outside it. Vailsburg includes the two smaller neighborhoods of upper Vailsburg and lower Vailsburg, both of which have Sanford Avenue as a focal point. Upper Vailsburg is closer to Maplewood and South Orange.
Vailsburg had existed as an independent municipality, and was incorporated as a borough by an act of the New Jersey Legislature on March 28, 1894, from portions of South Orange Township. Vailsburg was annexed by Newark on January 1, 1905, based on the results of a special election held on April 12, 1904. The borough was named for Dr. Merit H. Cash Vail, a physician and politician who was a major landowner and advocate for an independent municipality.
In the mid-1890s, Vailsburg had been proposed as one of the municipalities that would form a "Greater Orange", in an effort to avoid piecemeal annexation by an expanding Newark. Vailsburg was the last independent suburb to be annexed to Newark, in 1905, during a failed attempt by the mayor of Newark to absorb Kearny, East Orange, Belleville, and Harrison. The district today stands out from the rest of Newark like a peninsula and is separated from the rest of the city by the trench of the Garden State Parkway.