They face competition from American football, basketball, baseball and ice hockey of course as the country’s big sports.
But participation is high with 25m people in the US playing the sport and more than 3m registered in US Soccer’s youth programmes.
More people watching will also lead to more young people being inspired, or so they hope.
Most stadiums are situated in downtown areas to attract the younger “millennial” fans born after 2000 who MLS believe are mostly more interested in watching football than baseball which as an ageing audience.
Average attendances are around the 21,000 mark making it the seventh-highest compared to the other top leagues across the globe.
There is no doubt MLS is growing but the standard of football still needs to improve before it can challenge the big leagues for the top players when they are in their prime.
For now it is about continuing to grow and it looks set to be an interesting journey.