National (USA):
American Composers Alliance
American Composers Forum
American Music Center
American Society of Composers, Authors, and Publishers (ASCAP)
Broadcast Music, Inc. (BMI)
College Music Society (CMS)
Electronic Music Foundation
International Computer Music Association (ICMA)
National Association of Composers-USA (NACUSA)
Society for Electro-Acoustic Music in the United States (SEAMUS)
Society of Composers, Incorporated (SCI)
By State:
Iowa Composers Forum
Oklahoma Composers Association
Wisconsin Alliance for Composers
Foundations, funding organizations:
American Composers Forum
American Music Center
Argosy Foundation Contemporary Music Fund
The ASCAP Foundation
Barlow Endowment
Chamber Music America
Fromm Foundation
Guggenheim Foundation
Jerome Foundation
Koussevitzky Foundation
MAP Fund
Meet The Composer
National Endowment for the Arts