Evolving from the 19-bed Mahopac Emergency Hospital, Putnam Community Hospital opened its doors in October 1964 as a 66-bed voluntary hospital serving the needs of a community of 45,000. In 1973, the Reed Building addition was constructed which created additional bed capacity and a new emergency room. In 1985, a reorganization took place in which the hospital changed its name to Putnam Hospital Center and established a parent company (Putnam Center, Inc.) and a foundation (Putnam Hospital Center Foundation); both the hospital and the foundation became subsidiaries of the new parent company.
In 1987-88, the Certified Home Health Care Agency and the Long Term Home Health Care Program were added in order to accommodate the changes in how patient care was being provided. In 1990, the 20-bed adult psychiatric unit was constructed in response to the community's need for mental health services. This was followed in 1994 with the Celia Dill Dialysis Center for outpatients. In February 1999, a new birthing center was opened and in June of 2001, a new building on campus was opened with a state-of-the-art ambulatory surgery unit, MRI center, pain management program, outpatient radiology and physical therapy departments, 36 physicians' offices and administrative offices. A new two-story 20,000 square foot building housing a new and expanded emergency department and additional physicians' offices was opened in May 2003.
In June 2008, PHC opened the Camarda Care Center, a five-story 113,000 square foot patient building to house a new cancer center with radiation therapy, private patient rooms, physician offices and a hospital/community use conference center.