Penal is a town in south Trinidad, Trinidad and Tobago. It lies south of San Fernando, Princes Town, and Debe, and north of Moruga, Morne Dia…Penal is a town in south Trinidad, Trinidad and Tobago. It lies south of San Fernando, Princes Town, and Debe, and north of Moruga, Morne Diablo and Siparia. Penal is noted as a heartland of Hindu and Indo-Trinidadian culture.