Palacio de la Marquesa de Sonora, Palace and cultural monument in San Bernardo Street, Madrid, Spain

The Palacio de la Marquesa de Sonora stands at 45 Calle de San Bernardo, built of granite, red brick and Colmenar stone. It has three floors, a lobby, a branching grand staircase and a main courtyard, with stables and coach houses at the rear. Corner towers with slate spires were added between 1942 and 1947 by architect Javier Barroso.

In 1745 Antonio José Álvarez de Abreu, Marquis of Regalía, bought the Casa Grande and adjoining buildings on the site. Ventura Rodríguez drew plans in 1752, but the palace was not built; in 1763 Bernardo de Grimaldo commissioned José Serrano, who integrated the complex around a courtyard. A fire destroyed it on 17 August 1789, and the Marchioness of Sonora had Evaristo del Castillo rebuild and enlarge it, completed in 1828.

The palace shapes the character of this central Madrid street with its symmetrical neoclassical facade that commands attention from passersby. Its presence reflects how grand residences once defined the status and influence of the Spanish nobility in the city.

The building sits in a lively city-center area and is easy to reach on foot or by public transport. Since it now serves governmental functions, interior access is restricted, but visitors can view the exterior facade from the street.

The palace was recorded on Spain's heritage register, the Bien de Interés Cultural, on 31 July 1995. Its corner towers with slate spires were added between 1942 and 1947 by the architect Javier Barroso, in the neo-Herrerian style typical of that era.