River Edge is a Borough in Bergen County, New Jersey, United States. As of the United States 2000 Census, the borough population was 10,946. The 2007 Census estimate was 10,721. Riverside was incorporated as a borough by an Act of the New Jersey Legislature on June 30, 1894, as the Borough of Riverside from portions of Midland Township, at the height of the "Boroughitis" phenomenon then sweeping through Bergen County, based on the results of a referendum held the previous day. On December 1, 1930, the borough's name was changed to River Edge.