Bullseye target shooting? NRA and CMP
Muzzle loading? NMLRA
Trap shooting? ATA
Skeet shooting? NSSA
Practial Pistol? USPSA
Action Pistol? NRA
Defensive Pistol? IDPA
Metallic Silhouette? IHMSA (pistol) NRA (rifle & BPCR)
Cowboy shooting? SASS
Most if not all of these sanctioning organizations have websites with club locators.
Google, man, google.