There are three primary organizations that are involved in youth soccer activities in the United States:

1. The NCAA (large college) and NAIA (small college) for college soccer
2. The NFHS and its affiliated State organizations for high school soccer
3. The USSF for club style soccer organizations

As an interesting aside: for those of you who might be watching games from different leagues and see a ruling made, thinking "hey, that's not the way the rules are...", there is an excellent reference available. A Comparative Study of Rules and Laws by Don Dennison (National Clinician of the NISOA) showing each point of difference among the leagues' rules.

National Collegiate Athletic Association — NCAA

The NCAA is organized around the largest colleges and universities in the United States. It organizes all athletics for these schools, the information for soccer being found here (men's) and here (women's).

National Association of Intercollegiate Athletics — NAIA

The NAIA is similar in structure to the NCAA but is set up to serve the smaller U.S. universities and colleges. As with the NCAA site, there is a sub-page for men's and women's soccer.

National Federation of High Schools — NFHS

The NFHS organizes all of the State high school organizations and including the sporting activities. Soccer-specific information is pretty limited but one of the most valuable resources on the site is probably the list of participating State organizations and their contact info.

United States Soccer Federation — USSF

The USSF is the top of the organizational stack of club soccer organizations in the US. The relationships among the subordinate organizations can be seen here. The USSF is a US organization subordinate to the international FIFA (Fédération Internationale de Football Association) which itself holds a number of international youth soccer tournaments.

The several youth soccer organizations described below are National Affiliate members of the USSF. Each of them has a slightly different approach to the relationship between competetiveness and participation and this focus is the major topic of discussion. Some of them maintain their own sub-organizations of coaches, referees, etc., and some simply rely on the USSF structure, though all of them derive their sanction from the USSF.

United States Youth Soccer — USYS

USYS offers both recreational and competitive programs. The recreational programs are for players primarily interested in fun, fitness and friendship. It also offers highly competitive or "select" leagues for the more advanced player.

American Youth Soccer Association — AYSO

AYSO has been based on the philosophies of "Everyone Plays" and "Balanced Teams" requiring every player to play at least half of every game and that individual teams are balanced every year to assure fair play.

Soccer Association for Youth — SAY

As with the AYSO, SAY is dedicated to participation. Its goals are that teams are balanced and that every child must play at least half of every game. Its claim to fame, then, is that it offers a low-cost option for creating and maintaining a league. SAY membership includes many free items such as rulebooks for coaches and administrative handbooks, among other amenities.

U.S. Club Soccer

The best way to describe the focus of U.S. Club Soccer is to look at their Mission Statement:

“To Create, Develop, and Grow the best USSF sanctioned organization to foster the growth and development of club soccer programs throughout the United States. The result of which will be to improve the level of play of the competitive soccer player, and thereby the U.S. national teams and professional leagues.”

It's quite clear that their goal is to aggressively promote highly competetive soccer!