I couldn't find specific information about the "Amateur Athletic Unions of the US Inc" with the EIN provided (463636444) or related to the website leaguelineup.com. However, it appears there might be confusion with the well-documented Amateur Athletic Union of the United States (AAU). Below is an article about the AAU, which is a prominent organization in the United States:

Amateur Athletic Union of the United States

The Amateur Athletic Union of the United States (AAU) is a prominent multisport organization dedicated to promoting and developing amateur sports and physical fitness programs across the U.S.

History

The AAU was founded on January 21, 1888, by James E. Sullivan and William Buckingham Curtis, with the goal of establishing common standards in amateur sports. Initially, it was a leader in international sports, representing the U.S. in various international sports federations and closely working with what is now the United States Olympic & Paralympic Committee to prepare athletes for both Summer and Winter Olympic Games.

Mission and Philosophy

The AAU's mission is centered around providing sports opportunities for all ages and backgrounds, with the philosophy of "Sports for All, Forever." It emphasizes the development of youth athletes nationwide through numerous national championships and local events.

Sports Governance

The AAU serves as the governing body for over 45 sports programs, including basketball, boxing, gymnastics, handball, swimming, diving, water polo, wrestling, weight lifting, track and field, and others. It supervises tryouts for Olympic competitors and plays a significant role in supporting U.S. Olympic athletes.

Structure

The AAU is divided into 55 district associations, which collectively organize over 250 national championships and more than 30,000 age division events annually. These events attract over 900,000 participants and involve more than 100,000 volunteers.

Growth and Initiatives

The AAU continues to grow, with its membership numbers increasing annually. It focuses on creating partnerships with different sports organizations, government agencies, and municipalities to promote sports and health benefits for participants. Notable partnerships include hosting major tournaments at the ESPN Wide World of Sports Complex.

Legacy

Many future World and Olympic champions have participated in AAU events, such as the Junior Olympic Games, which were introduced in 1949. The AAU also awards the James E. Sullivan Memorial Trophy annually to the nation's outstanding amateur athlete.

[1] https://en.wikipedia.org/wiki/Amateur_Athletic_Union [2] https://www.britannica.com/topic/Amateur-Athletic-Union-of-the-United-States [3] https://www.sportsdestinations.com/sports/association-games/amateur-athletic-union-34141 [4] https://www.guidestar.org/profile/35-6057862 [5] https://www.causeiq.com/organizations/amateur-athletic-union-parent-organization,356057862/