There are 21 US Post Offices in Passaic County serving a total of 449,863 residents equating to 21,422 residents per post office. It's estimated that approximately 718,032 packages are handled across the 21 county post offices annually. Passaic County (/p\u0259\u02c8se\u026a.\u1d7bk/ p\u0259-SAY-ik, locally /p\u0259\u02c8se\u026ak/ p\u0259-SAYK) is a county located in the U.S. state of New Jersey. As of the 2010 Census, the population was 501,226, reflecting an increase of 12,177 (+2.5%) from the 489,049 counted in the 2000 Census, retaining its position as the state's ninth-most populous county. As of 2015, the county's Census-estimated population was 510,916, representing a 1.9% increase from 2010. Its county seat is Paterson. Passaic County is part of the New York metropolitan area. The most populous place was Paterson, with 146,199 residents at the time of the 2010 Census, more than 29% of the county's population, while West Milford, covered 80.32 square miles (208.0 km2), the largest total area of any municipality, more than 40% of the county's area. Passaic County was created on February 7, 1837, from portions of both Bergen County and Essex County. Northern Passaic This wide area has significant less pockets of population, low building density, low poverty and low crime rates. Within this area are many stable, mixed and middle-to-high income areas of diverse populations. For example, north of Paterson have well-kept suburban areas such as Wayne Valley, Pines Lake, Packanack Lake, Wayne Hills, Black Oak, Pointview Estates, and Preakness in Wayne, New Jersey and North Haledon, New Jersey."