Structure of Legion of Mary
The basic unit of the Legion is called a Praesidium, which is normally based in a parish. The Praesidium, usually a group of 3–20 members, meets weekly in its parish.
The Curia is the next level, each supervising several Praesidia.
The next level is the Comitium, which is in charge of several Curiae, usually over an area like a medium city or a part of a province.
The next level is the Regia, which is in charge of larger territories like a province or state (like in the US and Brazil).
The Senatus is the next level, and it generally has control over the Regiae in a very large area, usually a country or a very large territory.
The Concilium is the highest level and has its seat in Dublin. It has control over the whole Legion.
Each level of the Legion has the same officers:
President, Vice-President, Secretary, Treasurer, Spiritual Director. The last is always in the clergy, but all other offices are held by the laity. All positions regardless of responsibility are voluntary and the Legion as no paid workers.