The links here are for the main governing bodies of the sport for youth basketball. Most rules are similar but each league may have specific differences in rules. Also, each organization may or may not have affiliates in your area.
Amateur Athletic Union – aausports.org
Boys and Girls Clubs of America – bgca.org
International Basketball Federation - https://www.fiba.basketball/
National Junior Basketball League (NJB) – njbl.org
Triple Crown Sports – triplecrownsports.com
USA Basketball (Team USA) – usabasketball.com
United States Junior Nationals – USJN.com
United States Specialty Sports Association (USSSA) – usssatoday.com
Youth Basketball Organization of America – yboa.org
Blue Star Basketball – bluestarbb.com
Coach’s Clipboard – coachesclipboard.net
Guide to Coaching Basketball – guidetocoachingbasketball.com
Hoop Group – hoopgroup.com
SoCal Hoops – socalhoops.com
Tommy’s Basketball Playbook – angelfire.com