Chicago-based Northwestern Medicine and Crystal Lake, Ill.-based Centegra Health System signed a definitive agreement to merge, Northwestern announced June 12.
Northwestern and Centegra's governing boards have both approved the affiliation, and the organizations have garnered regulatory approval.
Officials said the three-hospital Centegra system will officially integrate into Northwestern Sept. 1.
"Together with Centegra, Northwestern Medicine will explore opportunities to expand and enhance clinical care offerings to patients in Northern Illinois," said Dean M. Harrison, president and CEO of Northwestern Memorial HealthCare. "Our shared goal is to provide patients with greater access to breakthrough treatments and specialized care, close to where they live and work."