Section 8559 Of Article 2. General Definitions From California Government Code >> Division 1. >> Title 2. >> Chapter 7. >> Article 2.

. (a) A "mutual aid region" is a subdivision of the state emergency services organization, established to facilitate the coordination of mutual aid and other emergency operations within an area of the state consisting of two or more county operational areas.
  (b) An "operational area" is an intermediate level of the state emergency services organization, consisting of a county and all political subdivisions within the county area.