Several ethnic and special interest branches, along with affiliated organizations, have formed to focus on unique genealogical interests or problems in a specialized research area. These branches and affiliated organizations operate under the MGS umbrella or similar rules, yet they are individual organizations with their own officers, meetings, and dues structures. They hold their own meetings and conduct projects of interest to their members. Some publish their own newsletters. Membership in any branch, subgroup or affiliated organization is separate from MGS membership. You may apply for membership in as many branches or affiliated organizations as you wish. Branch meetings are publicized in the MGS newsletters.

From the beginning, MGS members have seen that a thorough understanding of the history, laws, customs and records in each ethnic area is essential for effective genealogical research. MGS and the branches work together to offer a wide range of educational and research opportunities for members and the general public.