Guanabara Palace, Neoclassical palace in Laranjeiras, Rio de Janeiro, Brazil

Guanabara Palace is a neoclassical building in Laranjeiras with formal symmetrical design, white columns across the front, and large windows on multiple levels. The layout follows classical principles and creates spacious rooms filled with natural light throughout the structure.

Construction began in 1853 for the Portuguese José Machado Coelho, and the Brazilian imperial family bought the house in 1864; architect José Maria Jacinto Rebelo renovated it, and from 1865 it was the residence of Princess Isabel and the Count of Eu, known as Paço Isabel. Confiscated after the 1889 proclamation of the Republic, it was renamed Guanabara and received an eclectic facade under Francisco Marcelino de Souza Aguiar in 1908. It served as official residence for presidents including Getúlio Vargas, was attacked by Integralists in 1938, and in 1960 became the seat of the government of the state of Guanabara, a role kept after the 1975 merger with Rio de Janeiro state.

The palace's name comes from Guanabara Street, now Pinheiro Machado Street, where it stands. When Princess Isabel and the Count of Eu lived here, the approach along Paissandu Street was lined with a hundred imperial palms (Roystonea oleracea). Today the building is the working seat of Rio de Janeiro state's government, not a museum.

The palace is a working government seat on Rua Pinheiro Machado in Laranjeiras, so visits are normally limited to the exterior; the annex building, inaugurated in 1968, houses the vice-governor's office and Civil House sub-secretariats. Do not confuse it with Laranjeiras Palace, the governor's official residence, two blocks away on Rua Paulo Cesar Andrade.

The palace's ownership was disputed for 125 years: Princess Isabel sued in 1895, and only on 28 August 2020 did the Supreme Federal Court close the case in favour of the Union. The imperial family never received compensation for the expropriation.