Seattle Sounders FC joined MLS in 2009 and quickly became one of the league's best-supported clubs, regularly drawing more than 30,000 fans to Lumen Field. The Sounders have won the MLS Cup twice, in 2016 and 2019, several U.S. Open Cups and the 2022 CONCACAF Champions League, becoming the first MLS team to win the modern competition.
Seattle Sounders FC
Stadium photo: "Smart Destinations", GoSeattleCard.com, and Go Seattle Card Blog, CC BY-SA 2.0, via Wikimedia Commons