Residencia El Messidor, French-style castle in Villa La Angostura, Argentina.

Residencia El Messidor is a two-storey French-style manoir with a basement, built of local granite with a grey slate roof and cypress wood panelling brought by barge from Bariloche. Inside are a large dining room, living rooms with paintings by Juan Carlos Castagnino and Antonio Berni, and a circular library. The upper-floor rooms and terrace face Lake Nahuel Huapi and the Quetrihué Peninsula.

Sara Madero de Demaría commissioned architect Alejandro Bustillo to design it in 1940, with construction finished in January 1942. Since 1964 it has served as the official residence of the Neuquén provincial government.

The name refers to the tenth month of the French Revolutionary calendar, whose golden ears of grain gave it the meaning "month of gold". The residence keeps a French manoir character, with geometrically ordered gardens of coihues, arrayanes, pines and chestnuts around the house.

The residence is not open to the public. When no special guests are staying, vehicles may drive the circuit through the gardens without stopping or getting out. Access to the house itself requires an invitation from the governor of Neuquén.

The gardens mix native coihues, arrayanes and maitenes with exotic pines, chestnuts, birches, oaks and walnut trees. Alejandro Bustillo built the exterior in local granite because owner Sara Madero de Demaría feared fire, and the cypress interior wood was brought by barge from Bariloche.