Partidos of Buenos Aires

They are formally considered to be a single administrative unit, usually contain one or more population centers (i.e., towns and cities), and are divided into localidades.

At the head of every partido, the cabildo appointed a rural judge called Alcalde de la Santa Hermandad.

The judge, or alcalde, had the mission to maintain the law and order in the surrounding rural area of Buenos Aires, fighting against cattle raiders.

The alcalde was helped by a constabulary called Santa Hermandad (Holy Brotherhood) created in the late 15th century by the Catholic Monarchs and transplanted to the colonies.

In 1821 the Governor Martín Rodríguez and his minister Bernardino Rivadavia dissolved the cabildos and since then was the governor itself who appointed the judges, now called Juez de Paz (Justice of the Peace), his administrative territory was called Partido judicial (Judicial district) hence the name of the subdivision.