What is the difference between a chapter and an affiliate?

Answer

Affiliates are green building groups that existed before the creation of the USGBC chapter network. Because these groups shared a similar mission with that of USGBC, we made them affiliates rather than start new chapters to serve the same area. There are five in the U.S. As part of their affiliation agreement with USGBC, they agree to promote USGBC programs and perform many of the same functions as a chapter. By their very definition (as predating the USGBC chapter network) there can be no more affiliates.