The municipalities of Puerto Rico number seventy-eight and they make up the smallest electoral division in Puerto Rico. Each municipality is led by a mayor and divided into barrios, though the latter are not vested with political authority. Geographically, a municipality has a urban core that consists of either a town or a city. Urban cores with a population of 50,000 or above are considered cities, while those under 50,000 inhabitants are terms towns.
There are no first-order administrative divisions as defined by the United States Government, but Puerto Rico has 78 municipalities or "municipios" at the secondary order. For U.S. Census purposes, the municipalities are equivalent to counties. They are conveniently grouped into eight electoral districts, which do not possess administrative functions. In 1991, the Autonomous Municipalities of the Commonwealth of Puerto Rico Act was passed as a strategy for the decentralizing control and for improving government services to the people.
Every municipality is composed of several barrios, except for Florida which has only one barrio. The municipality of Ponce has the largest number of barrios, 31.
Every municipality (except San Juan) also has an urban area made up of one or more barrios. When the urban area is made up of only one barrio, it is called "Barrio Pueblo". Some urban areas are made up of multiple barrios: Ponce's urban area, for example, is made up of 12 barrios. All of San Juan's barrios are urban barrios, and the municipality of San Juan is composed of urban barrios only - thus, the entire municipality of San Juan consists of one large urban zone only.
Every municipality's urban zone is named by the same name as the municipality. For example, the municipality of Caguas has an urban zone called Caguas - just like the municipality. Some municipalities' urban zones are termed "pueblo" (town) while others are termed "ciudad" (city). The difference resides in the population of the municipality: if the municipality has an urban zone below 50,000 inhabitants, then its urban zone is called a pueblo. If a municipality has a population above 50,000 inhabitants in its urban zone, then its urban zone is called a ciudad.
36 of the 78 municipalities currently experience a budget deficit, putting 46% of the municipalities in financial stress. In total, the combined debt carried by the municipalities stands at about $590 million USD.[a]
In October 2009, a Puerto Rican legislator proposed a bill that would reduce to 20 the 78 municipalities currently making up the Island. The bill called for a referendum to take place on June 13, 2010, and which would let the people decide on the matter. The bill never made into law.
It was not the first time that an attempt to consolidate municipalities had failed. In 1902 the Puerto Rico legislature, under pressure from the US.-appointed governor of the Island, passed a law consolidating the then-76 municipalities of Puerto Rico into 46. The law was repealed three years later.
A legislator's proposal of Puerto Rico's future set of municipalities and their boundaries
The proposed twenty new municipalities (in bold) and the existing municipalities that would have made them up:
^An Act: To amend Sections 1 and 2 of Act No. 100 of June 27, 1956 Act No. 81 of August 30, 1991: Autonomous Municipalities Act of the Commonwealth of Puerto Rico. In An Act: To amend Sections 1 and 2 of Act No. 100 of June 27, 1956, Act No. 66, 3rd Session of the 13th Legislature of Puerto Rico. April 14, 1998. Retrieved November 22, 2009.
^Ponce. Proyecto Salon Hogar. Map of Barrios of Ponce. (Map with fully urbanized barrios conglomerated and merged as "Zona Urbana". Barrio not labeled is named "Machuelo Abajo".) Retrieved November 30, 2009.