Ilha Fiscal is an island in Guanabara Bay, bordering the historic city center of Rio de Janeiro, in southeastern Brazil.
Originally named by Europeans as Ilha dos Ratos, its current name comes from the fact that the customs department has been stationed there before Guarda Fiscal, serving the port of the then capital of the Empire in the nineteenth century. The island became famous for having housed the famous Baile da Ilha Fiscal, the last big party of the Empire before the coup d'état that proclaimed the Republic in November 1889.
Ilha Fiscal now houses a museum of cultural history that is maintained by the Navy of Brazil.