Debatable. It's still smaller than hockey but is growing while all of the Big Four are declining. And it's aired by ESPN, which the NHL isn't (mostly due to lack of interest). Soccer is on its way into the Big Four/Five, and hockey might be on the way out.
Boston, New York City (9 teams), Philadelphia, Washington (plus 2 in Baltimore), Miami, Detroit, Chicago (5), Minneapolis, Dallas, Denver, Phoenix, Los Angeles (8), San Francisco Bay Area (5)
Subject to rapid change depending on which local taxpayers will shell out a billion dollars for a stadium for teams to make a cash grab and run later.
your head
https://www.jetpunk.com/user-quizzes/202698/california-pro-sports-teams
Subject to rapid change depending on which local taxpayers will shell out a billion dollars for a stadium for teams to make a cash grab and run later.