Castle of La Atalaya, Neoclassical castle in Canteras, Cartagena, Spain.

Castle of La Atalaya is an 18th-century fort on Monte Atalaya, in the Canteras district of Cartagena, Murcia, at 242 m above sea level. Its plan is an isosceles trapezoid with five bastions at the vertices plus one on the south side, surrounded by a moat with a counterscarp. The entrance lies in the central southern bastion, leading to a vestibule, vaulted garrison rooms, embrasures and a cistern.

A watch post stood on Monte de la Atalaya since the late Middle Ages, warning of pirate raids and attacks from the Nasrid Kingdom of Granada. In 1706, during the War of the Spanish Succession, the English occupying the city for Archduke Charles built two forts here. The engineer Pedro Martín-Paredes Cermeño designed the present castle in 1766, and works finished in 1777 under Charles III's military programme, protecting the Arsenal and La Algameca against landings.

The castle's name comes from the watch post on Monte Atalaya, used since the late Middle Ages to warn of pirate raids or attacks from the Nasrid Kingdom of Granada. In 1874, during the Cantonal Rebellion, the fort was renamed "castillo de la Muerte" while it was held by cantonalist forces besieged by the centralist army.

The castle stands at 242 m on Monte Atalaya, reached on foot from the Barrio de La Concepción; the slope and the ruined state of the walls call for sturdy shoes. It has been listed on Hispania Nostra's Red List of endangered heritage since June 2014, and the interior is unfenced and unguarded, so enter with care.

The castle was listed on Hispania Nostra's Red List of endangered heritage in June 2014, and ownership passed from the Ministry of Finance to Cartagena's city council only in May 2016. Neighbours from La Concepción, with groups such as Adepa and Aforca, have pressed for its repair without institutional response.