Branches of the SCA are setup based around a geographical area or an institution. Within the Kingdom of Ansteorra, these are the designations.
Kingdom: area ruled by a King and Queen
Principality: area within a kingdom ruled by Prince and Princess
Barony: area administered by a Baron and/or Baroness, the ceremonial representative(s) of the Crown
Province: equivalent of barony without ceremonial representative
Shire: local branch reporting directly to a kingdom or principality
Canton: local branch reporting through a barony
Riding: local branch reporting through a province
College: institutional branch based at a school, research facility, etc.
Stronghold: institutional branch based at a military installation
Port: institutional branch based at a military installation in situations where groups of members will be detached for long periods, as with ships at sea
For a list of the branches within Ansteorra, you can easily reference this list.
