The New Castle of Manzanares el Real, also known as Castle of los Mendoza, is a palace-fortress erected in the 15th century in the town of Manzanares el Real (Community of Madrid, Spain), next to the Santillana reservoir at the foot of Sierra de Guadarrama mountain range.
Its construction began in 1475 on a Romanesque-Mudéjar hermitage and today is one of the best preserved castles of the Community of Madrid. It was raised on the river Manzanares, as a residential palace of the House of Mendoza, in the vicinity of an ancient fortress that was abandoned once the new castle was built.
The castle now houses a museum of Spanish castles and hosts a collection of tapestries. It was declared a Monumento Histórico-Artístico in 1931. It is owned by the Duchy of the Infantado, but its management is the responsibility of the Community of Madrid.