The American Historical Association (AHA) is a nonprofit membership organization founded in 1884 and incorporated by Congress in 1889 for the promotion of historical studies, the collection and preservation of historical documents and artifacts, and the dissemination of historical research. As the largest historical society in the United States, the AHA serves as the umbrella organization for historians working in every period and geographical area.

Founded in 1907, the Organization of American Historians (OAH) is the largest professional society dedicated to the teaching and study of American history. The mission of the organization is to promote excellence in the scholarship, teaching, and presentation of American history, and to encourage wide discussion of historical questions and equitable treatment of all practitioners of history.

Part of the Gale Directoryl Library, the Encyclopedia of Associations provides information on tens of thousands of organizations. You can search by topic.