The Brazilian monitor "Alagoas" was the third ship of the river monitors built for the Brazilian Navy during the Paraguayan War in the late 1860s. "Alagoas" participated in the Passage of Humaitá in February 1868 and provided fire support for the army for the rest of the war. The ship was assigned to the Upper Uruguay () Flotilla after the war. "Alagoas" was transferred to Rio de Janeiro in the 1890s and participated in the Fleet Revolt of 1893–94. The ship was scrapped in 1900.