PILCMAYO, APOSTOLIC VICARIATE OF. - The mission of P., situated in the north-western part of Paraguay and the south-western part of Bolivia, was erected into a prefecture on 26 February 1925 with territory detached from the Apostolic Vicariate of the Chaco in Bolivia.
At that time the prefecture was in Bolivian territory, but in 1938 it became Paraguayan because almost all of its territory was included in the immense Bolivian region awarded in that same year by the Treaty of Buenos Aires to Paraguay following the last war.
