Four basic levels of organization exist in United States Masters Swimming.
CLUB: USMS is a grassroots organization, so the first and the most important level is the club. The club is your local workout group, which sets its own practice times, makes arrangements for its own pool use, and if it chooses, hires a coach.
LMSC: The second level is the Local Masters Swimming Committee (LMSC). This is the collection of clubs within a common geographic area. In Florida, there is the Florida Gold Coast LMSC, the Florida LMSC, and the Southeastern LMSC. The Florida Gold Coast LMSC includes Dade, Broward, Palm Beach, Martin, Monroe and eastern Hendry Counties, the Southeastern LMSC includes the panhandle west of the Apalachicola River, and the Florida LMSC is everything else.
ZONE: The third level is the zone, which consists of the LMSC's in specific sections of the country. LMSC officers represent their areas at an annual zone meeting. Minnows are in the Dixie Zone (purple on map, bottom right corner), which consists of seven LMSC's.
USMS: The fourth level is United States Masters Swimming (USMS), which provides administrative structure for Masters swimming and assistance to each of the other three levels. USMS is itself a member of FINA, the international amateur sports governing body.
All officers in the organizations -- club, LMSC, zone, and USMS -- are volunteers with the exception of a few top USMS officers. All committee members and chairs, at all levels, are volunteers. Your annual registration fee to the LMSC and to USMS provides the primary support for all activities of the groups.