This subseries contains correspondence, memos, ephemera, and meeting minutes, among other material, that describe McIlhenny's 55-year relationship with the Philadelphia Orchestra Association. The earliest record of membership is from 1937. Two years later McIlhenny was elected member of the Board of Directors, and the following year Vice Chairman. He also served as Chairman of the Artistic Policy Committee from 1967, a committee designed to make decisions about artists and programming, and was instrumental in organizing student concerts. McIlhenny also dedicated his time to fundraising, working on fund drives, marathons and the membership campaign. McIlhenny remained a contributor throughout his life.