Montclair (/mɒntˈklɛər/ or /mɒŋˈklɛər/) is a suburban township in Essex County, New Jersey, United States. As of the 2010 United States Census, the township's population was 37,669, reflecting a decline of 1,308 (-3.4%) from the 38,977 counted in the 2000 Census, which had in turn increased by 1,248 (+3.3%) from the 37,729 counted in the 1990 Census.