Provinces are administrative units in Just Cause (1).
They're the adminstrative units that compose San Esperito. Most provinces contain two villages, a Military base and two Gang villas. Some provinces are seperated from the main island and can only be reached by aircraft or boat. An example of this would be Provincia Rio de Negro and Isla San Cristobal, as they can only be reached by going by boat or aircraft as there is no bridge long enough to reach across the water.
Also certain provinces may have more settlements of one type than another province. Provincia Aguilar has no military settlements at all but mainly civilian settlements and is one of the few which are easy to takeover in terms of both cartel and village liberations. Provincia Octavia is known mainly for Mendoza International Airport which is one of the biggest settlements and also the only airport which has a name for it. Some provinces will be more valuable than others like La Perdida which plays host to Nuevo Estocolmo and the only military base which has a Rage Johnston F6 Comet; the most rarest plane in game. Most provinces have an airfield as well. Sometimes provinces may be seperated by a river or a large cliff drop which only a bridge can be used to get across. Knowing your way around the provinces is an excellent way to get around them and find settlements etc.
Liberations and mission availabilityEdit
At the beginning of the game, all provinces are under government control - government stable. At this point you can complete sidemissions for the Guerrillas, but there's no way to take over (liberate) any government controlled settlements. As the story progresses these slowly become politically unstable. This unlocks the Liberation missions, which allow Rico to help the guerrillas to take over government settlements. The last government controlled settlement in any province is automatically taken over by the guerrillas when all others have been liberated. When all settlements in a province are taken over, the province becomes guerrilla stable.
Guerrilla sidemissions; Cartel Villa take-overs and Rioja Cartel sidemissions are always available, regardless of the political stability as the conflict between the Riojas and Montanos doesn't affect the actual political stability of San Esperito. Guerilla sidemissions do count towards a tenth of control of a province but doing more than a certain amount won't count so libertaions have to be done. There is no way around it.
Oddly, being "guerrilla stable" does not eliminate the San Esperito Police Department and the San Esperito Military from the province. It just means that there will be so many Guerrilla patrol cars and Delta 5H4 Boxhead attack helicopters around that the governement forces will no longer be a major threat, unless you gain maximum Heat. The military seem to be the most aggressive at any heat level in Isla San Cristobal, probably due to the military fort on the east side of this province.