Rockleigh (pronounced ROCK-lee) is a borough in Bergen County, New Jersey, United States. As of the 2010 United States Census, the borough's population was 531, reflecting an increase of 140 (+35.8%) from the 391 counted in the 2000 Census, which had in turn increased by 121 (+44.8%) from the 270 counted in the 1990 Census. Bordering Alpine, a community ranked America's most expensive ZIP Code by Forbes, Rockleigh has a similar residential character, with large single-family homes on large plots of land.