Watch the map as the presidios appear in the order in which they were founded.
The first four protected the four Spanish military districts in Alta California; the fifth presidio was built after Mexico declared independence from Spain.
Learn more about the Spanish missions in California.
Note that many historians do not consider the barracks at Sonoma to be a true presidio, because it was not part of the Spanish system of military districts. However, presidios established in Arizona, Texas, and Mexico indicate that the use of the term was very informal, and would certainly apply to the military outpost at Sonoma.
Also see our Animated Mission Map.