A monastery was built there by the Christian monk Hilarion in the mid-4th century AD and is currently believed to be the site of a mosque dedicated to Saint George, known locally as al-Khidr.

During the Crusader-Ayyubid wars, Deir al-Balah was the site of a strategic coastal fortress known as "Darum" which was continuously contested, dismantled and rebuilt by both sides until its final demolition in 1196.

Since the outbreak of the Second Intifada in 2000, it has witnessed frequent incursions by the Israeli Army with the stated aim of stopping Qassam rocket fire into Israel.

[12] Up until the later Ottoman era, Deir al-Balah was referred to in Arabic as "Darum" or "Darun" which derived from the settlement's Crusader-era Latin name "Darom" or "Doron."

[16] Its city center is about 1,700 meters (5,600 ft) east of the coast while the ancient site of Darum was uncovered 3 kilometers (1.9 mi) to the south of central Deir al-Balah.

[20] Archaeological findings in Deir al-Balah revealed a large ancient Egyptian cemetery with graves containing jewelry and other personal belongings.

[24] According to local tradition and observations from Western travelers in the 19th century, the prayer hall of the Monastery of Hilarion is currently occupied by the Mosque of al-Khidr.

[27] Throughout early Muslim Arab rule and until the arrival of the Crusaders in the late 11th century, "Darum" normally referred to the southern district of Jund Filastin whose capital fluctuated between the towns of Bayt Jibrin or Hebron.

[26] The Fatimid caliph al-Aziz Billah (r. 975-996) granted his favored vizier, Yaqub ibn Killis, a fief in modern-day Deir al-Balah, as testified by an inscription dating to the 980s located in the city's al-Khidr Mosque.

[27] As described by William of Tyre, the fort was small, tantum spatium intra se continens quantum est jactus lapidis (containing inside as much space as a stone's throw) and square-shaped with four towers, one of which was larger than the others.

[31] The population of the village consisted of indigenous Eastern Orthodox Christians allied to and protected by the Crusader administration and garrison based in the fort.

[32] Following Amalric's withdrawal from his fifth offensive against Egypt in 1170, Muslim general Saladin, fighting on behalf of the Fatimids, attacked and besieged the fortress as part of his foray into the Crusader Kingdom of Jerusalem.

[33] After the Muslim army defeated the Crusaders in the decisive Battle of Hattin in 1187, their leader Saladin, by then the independent sultan of the Ayyubid dynasty, advanced south and captured both Ascalon and Darom by 1188.

"Darum", which is what the Muslims called the fortress village, was encased by a wall with 17 strong towers protected by a deep moat with stone-paved sides.

[30] Authority over Darum was assigned to Count Henry I of Champagne, but Richard later had the fortress demolished in July 1193 prior to withdrawing his forces from Ascalon.

[37] It became a halting post along the newly introduced regular mail routes connecting Damascus and Cairo, which were run by horse-mounted messengers with colored sashes.

[47] In 1878, the PEF's Survey of Western Palestine noted Deir al-Balah had grown to become a large village of mud houses "with wells and a small tower".

By April an aerodrome and an army camp were established there and Deir al-Balah became a launching point for British forces against Ottoman-held Gaza and Beersheba to the north and northeast, respectively.

A municipal council to administer the town was established by the British authorities in 1946, but it had limited jurisdiction over civil affairs and provided a few basic services.

[57] In the lead-up to the 1948 Arab-Israeli War, residents of Deir al-Balah participated in a local attack against the nearby kibbutz of Kfar Darom, despite being discouraged by Egyptian Army officers, but they were repelled and suffered casualties.

[61] In the name of pan-Arabism, the Egyptian state officially merged with the Gaza Strip and Syria between 1959 and 1961 as part of the short-lived United Arab Republic (UAR).

[62] During the Six-Day War in June 1967, Deir al-Balah's mayor Sulaiman al-Azayiza briefly led local resistance against the incoming Israeli Army until formally surrendering the city shortly thereafter.

[63] During the course of the Israeli occupation, Deir al-Balah's urban areas extended into lands designated for agriculture, largely as a result of building restrictions which hindered organized expansion.

[70] The IDF campaign, which was intended to target members of Hamas in the center region of the Gaza Strip, brought down multiple apartment buildings.

The Survey of Western Palestine related in 1875 that there were Greek inscriptions on one of the steps leading to the door at the southern wall while on the floor was a broken stone slab marked by two Maltese crosses, apparently resembling a tombstone.

[74] Prior to the predominance of orthodox Islam in Palestine, the region contained numerous domed structures dedicated to Muslim patron saints, among which was the Mosque of al-Khidr in Deir al-Balah.

In March 2016, the Ministry of Tourism and Antiquities in the Gaza Strip began the restoration of the Mosque of al-Khidr with financial support from UNESCO and the Nawa Foundation.

In order to alleviate losses resulting from a 10 kilometers (6.2 mi) fishing limit off the coast imposed by the Israeli Navy following Hamas's victory in the 2006 parliamentary elections, the Palestinian Authority Department of Fisheries has sought to construct eight artificial reefs in both Deir al-Balah and Gaza City.

The Palestinian president, Yasser Arafat, appointed Samir Mohammed Azayiza as mayor until 2000 when he replaced him with Sami Abu Salim, a wealthy businessman from the city.

[99] The services and functions of the municipality include city planning, infrastructure maintenance and repair, providing utilities, school administration and garbage collection.