Penalva do Castelo is a municipality in the district Viseu in Portugal. The population in 2011 was 7,956, in an area of 134.34 km². The present …Penalva do Castelo is a municipality in the district Viseu in Portugal. The population in 2011 was 7,956, in an area of 134.34 km². The present mayor is Francisco Lopes de Carvalho, elected by the Socialist Party. The municipal holiday is August 25.