Soccer is not THE sport in the United States, the history of soccer in US is one of the longest around, ideal next to that of the English or the Scottish.
After the English set out to form a set of rules for the game of soccer, these were quickly taken to the new World, where Americans learned to enjoy this rising sport, best next to another game that grew strong roots in the United States back then: baseball. Actually, the American Football Association is the 2nd earliest sports league in America, after the Major League Baseball one.
Undoubtedly, the history of soccer in United States didn't start with an expert league though (in terms of what we call professional today). The American Football Association, started in 1884, was a semi-professional competition including New England and some Midwest areas and it was a rather chaotic environment to play soccer in, however nevertheless it existed and progressing with each year.
A parallel soccer organization, the American Amateur Football Association was founded around the same time and the 2 coexisted until 1913, when they merged into the United States Football Association, the first fully expert soccer organization throughout the history of soccer in the US.
The US football association (or USFA) was one of the very first to join FIFA and as such, the United States team took part in the early World Cups, although the video game was starting to end up being outshined by baseball or basketball.
With American football likewise on the rise, the company embraced a new name to prevent any confusion and called itself the US Soccer Football Association. The United States soccer history would quickly witness a new modification in its governing body's name in 1974, when the USSFA dropped "Football" from its tag and rather adopted the title of United States Soccer Federation, which is still used today.
Lots of will question, if the history of soccer in US starts out so early, how come soccer is not the primary sport in USA? Well the truth is that the rather modest efficiencies from the males's nationwide side early on in the 20th century, integrated with the high increase of baseball, football, basketball and hockey, implied that the country quickly disliked soccer and considering that American kids had a lot of alternatives, soccer gradually went out of fashion.
However, with the increasingly excellent performances from the United States males's soccer team and the huge success of the ladies's soccer group (who handled to bring in the very first prizes in the history of soccer in US and is still among the world powers in the game today), soccer is climbing up back to its rightful location and with increasingly more American kids favoring it in school as a start-up sport, things look intense for the future of US soccer.