On March 22, 1958, Group Health Cooperative dedicates the Northgate Clinic. The clinic is designed by Paul Kirk and will win honors from the American Institute of Architects. Dr. William "Sandy" MacColl, a Group Health founder and its first pediatrician, becomes the Chief of Staff for the Northgate Clinic.
Group Health was nearly 11 years old. It had about 45,000 members, a hospital on Seattle's Capitol Hill, and a clinic in Renton.