Siguenza is a city in the Serranía de Guadalajara comarca, Province of Guadalajara, Castile-La Mancha, Spain.

Main sights include:

• Cathedral The cathedral is a large Gothic edifice of ashlar stone, though the lower levels show that it was built onto an earlier Romanesque cathedral. Its façade has three doors, with a railed court in front. At the sides rise two square towers, 164 feet high, built at different times, with merlons topped with large balls; these towers are connected by a balustrade which crowns the facade, the work of Bishop Herrera in the eighteenth century. The interior is divided into a nave and two aisles, in Gothic style. The main choir begins in the transept with a Renaissance altar built by order of Bishop Mateo de Burgos. In the transept is the Chapel of Saint Liberata (Librada), the female patron saint of the city, with a reredos and the relics of the saint, all constructed at the expense of Bishop Fadrique of Portugal, who is buried there. What is now the Chapel of St. Catherine was dedicated to St. Thomas of Canterbury by the English Bishop Jocelin. The chapel hoses the sepulchre of Martín Vázquez de Arce (Martin Vasques de Arze in the spelling of the time). Vázquez died in 1486 during the conquest of Granada and his brother Fernando, bishop of the Canary Islands, ordered a portrait in alabaster where he lies on his side while reading, in one of the finest examples of Spanish funerary art. It contrasts with the recumbent figures of his parents in the same chapel. The authors of the Spanish Generation of 1898 (Ortega y Gasset) drew attention to this statue naming him el doncel de Siguenza, "the boy of Siguenza", but Vázquez left a widow and children. Cardinal Mendoza is interred in the main choir. Beyond the choir proper, which is situated in the centre, there is the altar of Nuestra Señora la Mayor, in black marble from Calatorao and red marble, featuring spiral Solomonic columns. The main sacristy is also named as "of the heads". It was designed in 1532 by Alonso de Covarrubias and built by Francisco de Baeza and Martín de Vandoma. The portal is Renaissance, Plateresque, of 1573, in stone, the nuttree door has also Plateresque carvings and was damaged by a cat door and the Napoleonic troops. The half cannon vault features 304 big heads, all different, and 2000 smaller ones, hence the nickname of the room. The ceiling and the vitrals of the cathedral were damaged in the Spanish Civil War, with the reconstruction ending in 1947. Connected with the cathedral is a Florid Gothic cloister, the work of Bernardino de Carvajal. The rich tabernacle, with its golden monstrance, was given by Cardinal Mendoza. The chapter house contains a number of paintings. It is not known with any certainty at what period this church was begun, though it appears to date from the end of the twelfth century. The image of Nuestra Señora la Mayor, to whom the church is dedicated, dates from the end of the twelfth century; it was taken to the retro-choir in the fifteenth century, the Assumption being substituted for it on the high altar.
• Castle With foundations dating back to the 5th century, Siguenza Castle was extended by the Moors in the 8th century and retaken by the Christians under Bernard of Agen in 1123. In the late 18th century, Bishop Juan Díaz de la Guerra changed the appearance of the castle from a fortress into an episcopal palace with additional windows, balconies and stables. However, in 1808 during the War of Spanish Independence the castle was taken by the French who seriously damaged it and looted all its riches before it was recaptured by El Empecinado. The episcopal palace was further devastated by fire in the 1830s and had to be abandoned. In 1976, after comprehensive restoration, the castle was opened as a parador luxury hotel. The official inauguration took place in 1978 with the visit of King King Juan Carlos and Queen Sofía. Decorated with banners and suits of armour, the huge lounge was originally the castle's dining room.
• Other buildings The Conciliar Seminary of San Bartolomé is the work of Bishop Bartolomé Santos de Risoba (1651). There is a smaller seminary, that of the Immaculate Conception, and a college. The College of San Antonio el Grande was formerly a university, founded in 1476 by the wealthy Juan López de Medina, archdeacon of Almazán, but its prosperity was hindered by the foundation of the University of Alcalá; in 1770 it was reduced to a few chairs of philosophy and theology, until it was suppressed in 1837.
  Other buildings include the ancient hermitage of Nuestra Señora, which according to tradition was originally the pro-cathedral; the Humilladero, a small Gothic hermitage, now a tourism office; the Churrigueresque convent of the Franciscans; the modern convent of the Ursulines, which was formerly the home of the choir boys; the hospital of the military barracks; and the Hieronymite college.