The castle of Soria and its walls are located on the so-called Castle Hill in the Spanish city of Soria, capital of the province of the same name.

The original city was heavily walled in its entirety, more than a square kilometre, with a double barrier and barbican, the castle being on the hill that bears its name, the original Mount Oria according to some authors, being one of the best defended in early 12th century Spain.

A Celtiberian castro has existed on the hill of the castle since at least the Bronze Age, as remains of a settlement have been discovered that was undoubtedly linked to the existence of Numantia. Bartolomé de Torres, in his Topografía de la ciudad de Numancia, states that the castle of this city took the name of Oria from a Greek knight called Doric, captain of the Dorians, who came to Soria from Achaia. Some historians deduce from this information that the first settlers of present-day Soria were the Dorians. However, nothing in this respect has been corroborated by archaeology and for another group of experts the first settlers of Soria were the Suevi, whose kings, according to Tutor y Malo in his Compendio historial de las dos Numancias, established one of their courts there. Both hypotheses have fallen into disuse with the passage of time because no document reliably proves them. In Roman times it continued to exist as a village of little importance.

During the Arab domination, the castle was no more than a simple watchtower or small fortress that watched over this area of the Duero and protected the Muslim town of Medina-Soria. The construction of the castle is attributed to Count Fernán González, although Soria was definitively conquered from the Muslims at the beginning of the 12th century by the Aragonese King Alfonso I the Battler married to the León queen Urraca I. His son Alfonso VII the Emperor built the inner barrier and Sancho IV the outer walls.

During the War of Independence, Marshal Michel Ney remained in the province of Soria until 1812. The French left Soria after entrenching themselves in the castle on 17 September 1812. Brigadier José Joaquín Durán conquered Soria on 18 March with the troops of the 6th Division of Soria, with an operation in which he planned to make small breaches or blast holes in different points of the wall, so that the French would only entrench themselves in the castle, as he had reports of two columns coming to the aid of the entrenched French. Months later, General Durquier entered Soria, remaining there for one day and marching on 13 September towards Navarre. General Tabuenca entered on the 14th and General Durán on the 16th. Durán remained in the city until the beginning of October, as he had to leave for Aragón, leaving a reinforced company garrisoned in Soria, which took part in security tasks, clearing rubble, policing, cleaning roads and streets, and collaborating in the demolition of the castle walls.

He ordered the destruction, in compliance with a superior order and the mandate of the Cortes de Cádiz (which had ordered the demolition of all the walls and castle). The demolition of the castle left the building in ruins, almost completely destroyed. After the conflict, the entire enclosure was abandoned.

In order to describe what this important castle was, we must start with the Plan of Soria drawn by Dionisio Badiola at the beginning of the 19th century, which faithfully shows the image of the castle in elevation, plan and profile before it was dynamited by General Durán.

The castle itself consisted of a powerful, slightly trapezoidal construction flanked by four small towers at the corners. At the front, at the main entrance, there was another slightly larger tower and at the rear, in the best-defended area, was the keep. Inside was the Patio de Armas (parade ground), around which the rooms were distributed and where the cistern was located. This structure was located to the east, close to the high inner wall, which was more or less on the surface of the hill. Another barrier, by way of access, started from the west and surrounded the previous one only on the side facing the town as far as the main entrance to the castle, which was already in ruins at the beginning of the 19th century. Within the walled enclosure was the church of San Salvador, which served as a chapel for the inhabitants of the castle and which was ruined at the beginning of the 17th century. This enclosure also housed one of the two aljamas of Soria (the other was located next to the Plaza Mayor) whose intellectual, economic and commercial activity was notorious.

The ruins of the keep, the inner walled enclosure and the remains of the outer barrier with its entrance flanked by two cylindrical cubes remain from the castle.

After the reconquest, the city of Soria was born in the shadow of its castle, extending along a wide and long ravine, between two hills, the Mirón and the castle. The natural boundary of the riverbed led to urban development towards the west, rising through the centre of the gorge to occupy the highest areas, forming the 35 Collaciones or parishes according to the 1270 Census ordered by King Alfonso X the Wise. The walled enclosure covered an area of around 100 hectares with a perimeter of 4100 m, the same length as the walled enclosure of Old Jerusalem. It seems to have been built during the 13th century in the time of Sancho IV, as a document from this period talks about the money destined for the "cerca de la viella" of Soria.

Starting from the Cerro del Castillo, it borders the cemetery to the south, continuing in a curve along Calle Santa Clara, Alberca and Puertas de Pro to the west, heading north. It passes through Santo Tomé and continues ascending until it reaches the height of Paseo del Mirón, takes an easterly direction looking for the hermitage of Nuestra Señora del Mirón and descends the hillside towards the Duero, where, skirting the river, it returns to the Cerro del Castillo. Important vestiges of all this enclosure remain with walls and cubes near the convent of Santa Clara, in the Paseo de Mirón, the descent to the Duero and in the Postiguillo, as well as some remains that support the houses in the street Puertas de Pro. The section that runs alongside the Duero is made of ashlar stones without cubes, since the river acts as a natural barrier, while the rest of the wall is built in ashlar or masonry, is higher and is reinforced with cylindrical cubes.

Along this wall there were six flanking gates with their respective cubes, four postiguillos (small open gates in the enclosure) and a gate (larger than these and smaller than those). None of them remain today (except for the Postigo de San Ginés and the Postiguillo de San Agustín), but their location and names are known. In the south, near the cemetery, was the Puerta de Valobos. Near the old convent of Santa Clara there was a postiguillo, that of Santa Clara, and near Alberca street was the Puerta de Santa Clara or Puerta Nueva, the last to be opened. The Puerta de Rabanera or Arco de Rabanera a little further on, in Calle Caballeros; the Puerta del Postigo in Collado and the Puerta del Rosario in the square that bears its name, opposite the church of Santo Domingo. The Puerta de Nájera or Puerta del Mirón gate opened to the north at the present-day exit to the road to Logroño. Next to the Duero was the Postigo de San Ginés and the Postiguillo de San Agustín (the only ones that remain), opposite the bridge the Puerta del Puente or Puerta de Navarra and a little further on the Postiguillo or Postiguillo de San Pelegrín.