Soviet Union | Boston | European Union | Union Army | rugby union | Union | Boston University | International Telecommunication Union | Boston College | trade union | Boston Celtics | Marylebone Cricket Club | Museum of Fine Arts, Boston | Union (American Civil War) | Lancashire County Cricket Club | Boston Bruins | The Boston Globe | Union Pacific Railroad | England national rugby union team | Sierra Club | Boston Marathon | American Civil Liberties Union | Wales national rugby union team | New Zealand national rugby union team | Ireland national rugby union team | Boston Symphony Orchestra | club | Western Union | Sgt. Pepper's Lonely Hearts Club Band | Club Brugge K.V. |
Williams was a member of the Congregational church, the freemasons, the American Law Institute, the Massachusetts Bar Association, Sigma Alpha Epsilon, the Harvard Club of Boston, the Union Club of Boston, the Brae Burn Country Club, and the Grange.