Hackensack Meridian Health Mountainside Medical Center, also known as Mountainside Hospital, is an acute-care hospital located in Glen Ridge, New Jersey, United States. The hospital has 365 beds and serves Northern Essex County. A part of the Hackensack University Health Network, Mountainside Hospital is one of only two for-profit hospitals in New Jersey. It is also a clinical campus and affiliate of the New York Institute of Technology College of Osteopathic Medicine and provides clinical clerkship education for the medical school's osteopathic medical students.