Revolution 3 Triathlon     https://rev3tri.com/  
 
Tri It Now  www.triitnow.com Great venue for beginners with pool swims at the Manassas Freedom Center!
Race categories include triathlon, duathlon, aquabike, aquathlon, tri-relay teams
Racine Multisports   www.racinemultisports.com  Multisport, running and open water swim races in MD & VA
Others 
Additional websites to find races:
 
For more information on USAT events and membership: