The Legion of Mary is the largest apostolic organization of lay people in the Catholic Church, with well over 3 million active members in almost every country of the world. It has been active in the United States since 1931, has been approved by the last 6 Popes, and was endorsed by the Second Vatican Council. The main purpose of the Legion of Mary is to give glory to God through the sanctification of its members.
 
The Legion of Mary is a lay Catholic organization whose members are giving service to the Church, on a voluntary basis, ail over the world. The object of the Legion of Mary is the glory of God through the holiness of its members developed by prayer and active co-operation in Mary’s and the Church’s work.
 
The Legion of May was founded by Frank Duff with a group of Catholic laywomen and Father Michael Toher. The first meeting was held in Myra Flouse, Francis Street, Dublin, Ireland, on September 7, 1921. In the first decade of its existence it consolidated itself in Ireland, Wales, and Scotland. In the second decade, the Legion spread rapidly through the United States, Canada, India, Australia, and Africa.
The third decade saw it span the length and breadth of Europe. Finally, the vast Spanish-speaking countries caught its contagious missionary zeal, so that the Legion exists on all continents.
 
Frank Duff’s profound insights into the role of the Blessed Virgin in the plan of Redemption and the role of the lay faithful in the mission of the Church form the basis of the Legion’s works.
 
The Legion does not require persons of special talent. Through spiritual formation and a program of works, it molds average Catholics of good will into apostles.
The first Praesidium (parish unit) was formed in the United States, at Raton, New Mexico in 1931 and was composed entirely of men.
 
The St. Louis regional Senatus of the Legion of Mary governs the Legion Councils in five (5) states: Nebraska, Iowa, Missouri, Oklahoma, Kansas, Colorado, Wyoming, Montana, Arkansas and Illinois (Except for the Chicago Archdiocese and Dioceses of Rockford, Joliet and Peoria, which are covered by the Chicago Senatus.)