American Radio Relay League (ARRL)
“ARRL is the national association for Amateur Radio in the US. Founded in 1914 by Hiram Percy Maxim as The American Radio Relay League, ARRL is a noncommercial organization of radio amateurs. ARRL numbers within its ranks the vast majority of active radio amateurs in the nation and has a proud history of achievement as the standard-bearer in amateur affairs. ARRL’s underpinnings as Amateur Radio’s witness, partner and forum are defined by five pillars: Public Service, Advocacy, Education, Technology, and Membership.” From the ARRL web page.
ARRL is a member-society of the International Amateur Radio Union (IARU) which represents radio amateurs throughout the world.