The BOMC is a Pennsylvania 501(c)3 corporation with research, charitable, and educational purposes. Among other things, the BOMC, and the related Magna Charta Research Foundation, seek to "encourage the study and practice of the Magna Charta, within its historical context, and the evolution of its meaning as represented in the concepts of self-determination and the rule of law." Towards this end, the BOMC preserves documents and literature relating to the Magna Charta, sponsors scholarships and educational programs, and works with the Magna Charta Trust in the United Kingdom in furtherance of that organization's preservational and educational goals. Notably, since 1993, the BOMC has held a seat on the Board of Trustees of the Magna Charta Trust.
Membership in the BOMC may be extended to men and women of good moral character who can establish through genealogical proofs (i.e., primary or acceptable secondary sources) their descent from one of the twenty five Magna Charta Surety Barons:
Descendants of the following non-Surety supporters of the Magna Charta are also candidates for membership in the BOMC: William III d'Aubigny, Hubert de Burgh, Alan of Galloway, William Marshall, Sr., and William IV de Warenne. Membership may also be considered for individuals of good moral character who, while not descended from a surety or non-surety supporter, have an interest in the purposes of the BOMC.
The BOMC maintains a partial list of "gateway" immigrants who descend from Magna Charta Barons. Many of these individuals and their descendants played significant roles in the history of the United States. For example, George Washington's family descend from William d'Albini, Lord of Belvoir Castle.
Among others, members of the BOMC have included: Frederick H. Winston, diplomat and founder of the law firm Winston & Strawn; Charles W. Darling, Assistant Secretary of the Navy; William S. Sessions, Federal Judge and Director of the FBI; Hugh Scott, U.S. Senator from Pennsylvania; Dorsey B. Hardeman, influential Texas politician; and, Martin W. Clement, 20th century railroad magnate. Recipients of the BOMC's Magna Charta Day Award include Sir Winston Churchill, General Douglas MacArthur, President Dwight D. Eisenhower, and Masters of The Rolls of England Lords Donaldson and Woolf.