Buenos Aires City Hall, Municipal government palace in Monserrat, Argentina

Buenos Aires City Hall is a Second Empire-style building on the north side of Avenida de Mayo at Bolívar, beside the Cabildo and facing Plaza de Mayo. Its façades are clad in simulated Paris stone, now covered by paint. The original 1893 structure has six floors, 31 meters to the roof and 48.2 meters to the tip of the central dome; a 1911–1914 annex nearly doubled its size.

Construction began in 1890 under Mayor Francisco Bollini and marks the start of a phase of major urban modernization. An annex was later added to accommodate the administrative needs of the growing city.

Decorative tilework and chandeliers from the adjacent Zuberbühler house, expropriated for the Avenida de Mayo, were salvaged and installed in the new city hall, where they remain today. Since 2015 the building has housed city government offices that report to the Casa de la Ciudad in Parque Patricios, and guided visits are run from the Casa de Cultura.

The building sits directly on Plaza de Mayo and is easy to spot from the street, especially if you visit Casa Rosada nearby. The interior remains in administrative use during weekdays, but you can view the exterior and surroundings at any time.

A time capsule was placed inside the cornerstone on New Year's Eve 1890 and holds objects from that era. This hidden memory documents what the city considered important at the beginning of its modern age.