Mountainside Hospital 1 Bay Avenue Montclair, NJ 07042 (973) 429-6000 Email Us Focused on medical excellence and community service for more than a century Patient focused, community oriented, conveniently located and equipped with technology that rivals the nation’s most prestigious healthcare systems, Mountainside Hospital offers a comprehensive and growing array of services delivered by caring and highly skilled medical professionals. We’re proud of the therapeutic and administrative upgrades we have made. We’re the convenient, friendly community hospital that delivers the quality care, medical excellence and technology on which you can depend. Mountainside Hospital has been serving Montclair and its surrounding New Jersey communities since 1891. The physicians, nurses and volunteers who are a part of the Mountainside family are also your friends and neighbors. We're your community, your hospital and your team, working hard on your behalf.