Units are vital components of ACBL. Their jurisdictional areas range in size from single cities to large states. Unit memberships range from fewer than 100 members to as many as 10,000 or more. Each unit is chartered by the ACBL Board of Directors and must function within the bylaws and regulations of ACBL. ACBL retains the right to amend, alter, or revoke a unit charter. The relationship between ACBL and its chartered units is that of independent organizations.