The political division of the Kingdom of Spain is based on the 8th Title of the Spanish constitution of 1978, which establishes three levels of territorial organization: municipalities, provinces and autonomous communities, the first group constituting the subdivisions of the second, and the second group constituting the subdivisions of the last. The State guarantees the realization of the principle of solidarity amongst all the constituent parts of the country.
The autonomous communities were constituted in exercise of the right to autonomy or self-government that the constitution guarantees to the nationalities and regions of Spain, while declaring the indissoluble unity of the Spanish nation. The autonomous communities constitute a highly decentralized form of territorial organization, but based on devolution, and thus Spain is not a federation, since the State is superior to the communities and retains full sovereignty. The Constitutional Court of Spain has labeled this model of territorial organization the "State of Autonomies".
The autonomous communities (comunidades autónomas in Spanish and Galician, comunitats autònomes in Catalan, autonomia erkidego in Basque) constitute the first order (highest) level of territorial organization of Spain. They were created progressively after the promulgation of the Spanish constitution in 1978, as the exercise to self-government of the "nationalities and regions" that constitute the Spanish nation. In the exercise of the right to self-government recognized in that article, autonomy was to be granted to:
Originally autonomy was to be granted only to the so-called "historical nationalities": Catalonia, the Basque Country and Galicia, regions with strong regional identities that had been granted self-government or had approved a Statute of Autonomy during the Second Spanish Republic (1931–1936).
While the constitution was still being drafted, and self-government seemed to be granted only to the "historical nationalities", there was a popular outcry in Andalusia, demanding self-government as well, which led to the creation of a quicker process for that region, which eventually self-identified as a "historical nationality" as well. In the end, the right to self-government was extended to any other region that wanted it.
The "historical nationalities" were to be granted autonomy through a rapid and simplified process, whereas the rest of the regions had to follow specific requirements set forth in the constitution. Between 1979 and 1983, all regions in Spain chose to be constituted as autonomous communities; four additional communities self-identify as "nationalities", albeit acceding to autonomy via the longer process set forth in the constitution.
While the constitution did not establish how many autonomous communities were to be created, on 31 July 1981, Leopoldo Calvo-Sotelo, then the prime minister of Spain and Felipe González, leader of the opposition in Parliament, signed the "First Autonomic Pacts" (Primeros pactos autonómicos in Spanish), in which they agreed to the creation of 17 autonomous communities and two autonomous cities, with the same institutions of government, but different competences. By 1983, all 17 autonomous communities were constituted: Andalusia, Aragon, Asturias, the Balearic Islands, the Basque Country, the Canary Islands, Cantabria, Castile and León, Castile–La Mancha, Catalonia, the Community of Madrid, Extremadura, Galicia, La Rioja, Navarra, the Region of Murcia and the Valencian Community. The two autonomous cities, Ceuta and Melilla were constituted in 1995.
Autonomous communities have a wide range of powers, but the devolution of power to the individual communities has been asymmetrical. The Constitutional Court has declared that the autonomous communities are characterized both by their homogeneity and diversity. Autonomous communities are "equal" in their subordination to the constitutional order, in their representation in the Senate of Spain, and in the sense that their differences should not imply any economical or social privilege from the others. Nonetheless, they differ in the process whereby they acceded to autonomy and their range of competences. The cases of the Basque Country and Navarra are exceptional in that the medieval charters (fueros in Spanish) that had granted them fiscal autonomy were retained, or rather "updated"; the rest of the autonomous communities do not enjoy fiscal autonomy.
All autonomous communities have a parliamentary form of government. The institutions of government of the different autonomous communities (i.e. the Parliament or the Office of the Executive) may have names peculiar to the community. For example, the set of government institutions in Catalonia and the Valencian Community are known as the Generalitat, the Parliament of Asturias is known as the Junta General (lit. General Gathering or Assembly), whereas Xunta in Galicia is the denomination of the office of the executive, otherwise known simply as the "Government".
The official names of the autonomous communities can be in Spanish only (which applies to the majority of them), in the co-official language in the community only (as in the Valencian Community and the Balearic Islands), or in both Spanish and the co-official language (as in the Basque Country, Navarre and Galicia). Since 2006, Occitan—in its Aranese dialect—is also a co-official language in Catalonia, making it the only autonomous community whose name has three official variants (Spanish: Cataluña, Catalan: Catalunya, Occitan: Catalonha).
The provinces (provincias in Spanish and Galician, províncies in Catalan, probintziak in Basque) are the second-level territorial and administrative divisions of Spain. The provincial scheme was created in 1833 by Javier de Burgos and based upon the limits of the old Hispanic kingdoms, though dividing them, if necessary, due to geographic and/or demographic reasons (i.e. to ensure a relative homogeneity in extension and population).
This scheme has undergone only minor adjustments since 1833, most notably the division of the Canary Islands into two provinces in 1927. There are fifty provinces in Spain.
The province is a local entity with juridic personality constituted by the aggregations of municipalities. The governance of provinces is carried out by Provincial Deputations or Councils, with the following exceptions:
The competences of the provinces vary amongst the autonomous communities they belong to. Since the creation of the autonomous communities their scope of action is minimal, with the exception of the historical territories of the Basque Country. In all cases, they are guaranteed a juridical status and autonomy to conduct their internal administration by the constitution.
The official names of the provinces can be in Spanish, the co-official language of the community they belong to, or both.
The municipalities of Spain (municipios or concejos in Spanish, concellos in Galician, municipis in Catalan, udalerriak in Basque), constitute the lowest level of territorial organization in the country, and are guaranteed a measure of autonomy by the constitution. The administration of the municipalities corresponds to the ayuntamientos (ayuntamientos in Spanish, concellos in Galician, ajuntament in Catalan, udalak in Basque) consisting of mayors and councillors, who are elected by universal suffrage.
The municipalities are the basic entities of the territorial organization of the State, the immediate channels of the citizens' participation in public affairs. The official names of the municipalities of Spain can be in Spanish—the official language of the country, in any of the co-official languages of the autonomous communities they belong to, if applicable, or in both.
All citizens of Spain are required to register in the municipality they live in, and after doing so, they are juridically considered "neighbors" (residents) of the municipality, a designation that grants them various rights and privileges, and which entail certain obligations as well, including the right to vote or be elected for public office in said municipality. The right to vote in municipal elections is extended to Spanish citizens living abroad. The Spaniard abroad, upon registering in a consulate, has the right to vote in the local elections of the last municipality they resided in. A Spanish citizen born abroad must choose between the last municipality his or her mother or father last lived in.
The autonomous communities have the right to establish additional territorial entities in their internal territorial organizations, without eliminating the provinces or the municipalities (even if the latter can have a different name). Catalonia had created two types of additional territorial entities: the comarques and the vegueries, both of which had administrative powers and were initially recognized in the last Statute of Autonomy (organic law) of the community, but The Constitutional Court annulled, among others, the parts that modified the territorial organization. Almost all communities have defined territorial entities (e.g. comarcas or merindades), but these do not have administrative powers and are simply geographic or historical designations.
One special case of such territorial entities is Western Sahara, formerly the colony of Spanish Sahara up to 1976, is disputed between Morocco, who controls 80% of the territory and administers it as an integral part of its national territory, and the Sahrawi Arab Democratic Republic, who controls and administers the remaining 20% as the "Liberated territories". The United Nations, however still considers Spain to be the administrating state of the whole territory, under the Non-Self-Governing Territories awaiting the outcome of the ongoing Manhasset negotiations and resulting election to be overseen by the United Nations Mission for the Referendum in Western Sahara.