The Port Arthur Clinic was conceived in 1923-24 when Doctors P.M. Ballantyne and Robert L. Harold joined John I. Pratt in the practice of medicine. They opened the first Port Arthur Clinic at 189 Arthur Street in the depths of the post-war depression. The practice survived these early years through the sale of alcohol by prescription and by selling radiology services to the Port Arthur General Hospital. Port Arthur prospered during the years 1925 to 1929 when Dr. G. A. Duff joined the clinic. Construction was completed on a new facility in 1930 and the practice continued to struggle until a mining boom hit the Thunder Bay area in 1934.
By signing medical contracts with all of the mining and timber companies in the area, the Port Arthur Clinic undertook to serve thousands of people in the area. This was accomplished by expanding the medical staff to enable them to cover Longlac, Jellicoe, Geraldton, etc. With the outbreak of war in 1939, and the resultant shortage of doctors, the Clinic doctors decided to restrict their practice to Port Arthur, and relinquished their contract work in the district. By 1942 the staff of the Clinic was reduced to six members, ending the war with five. When this number doubled by 1947, the Clinic was re-organized. A business manager was hired and a pension and insurance scheme was established for non-medical staff.
In 1951 a pharmacy was established in the Clinic and the Clinic building was further expanded to accommodate pediatric and x-ray departments.
In 1965 a new Clinic building was constructed to accommodate the expanded staff and services. The Port Arthur Clinic had become a multi-specialty clinic providing all services required by Northwestern Ontario.
In 1989 the upper floor was added to the Clinic to give it its present form.To meet the needs of outlying communities, the Clinic offers outreach services to serve them. Specialists from the Clinic travel to regional hospitals to provide cost-effective specialty care in these communities. With the shortage of family physicians in Thunder Bay, Clinic hours and urgent care services have been expanded weekdays and extended to weekends.
The Clinic continues to plan for future needs of the Northwestern Ontario community.
In August 2003, the Port Arthur Clinic reorganized and changed its name to The Port Arthur Health Centre.