Allegheny County Library Association
Bedford County Federated Library System
Bradford County Library System
Butler County Federated Library System
Centre County Federation of Public Libraries
Crawford County Federated Library System
Cumberland County Library System
Delaware County Library System
Franklin County Library System
Jefferson County Library System
Lackawanna County Library System
Lawrence County Federated Library System
Library System of Lancaster County
Somerset County Federated Library System
Washington County Library System
The Association of Pennsylvania Public Library Systems (APPLS) 