Peñaranda de Duero Castle is a well-preserved Gothic castle located in Peñaranda de Duero, in the province of Burgos. Originally built in the 10th century, it was significantly renovated in the 15th century by the Counts of Miranda del Castañar.
The castle features a four-storey keep with a roof terrace, battlements and a gallery of machicolations. It stands at the start of a defensive wall that once surrounded the town, of which only the crenellated arch of "Las Monjas" remains.