Lajjun (, al-Lajjûn) was a Palestinian Arab village located in Mandatory Palestine, northwest of Jenin and south of the remains of the biblical city of Megiddo. Named after an early Roman legion camp in Syria Palaestina province called " Legio", located at the village site, Lajjun's history of habitation spanned some 2,000 years. Under Abbasid rule it was the capital of a subdistrict, during Mamluk rule, it served as an important station in the postal route and during Ottoman rule, it was the capital of a district that bore its name. After the collapse of the Ottoman Empire towards the end of World War I, Lajjun and all of Palestine was placed under the administration of the British Mandate. The village was depopulated during the 1948 Arab-Israeli War, when it was captured by Israel. Most of its residents subsequently fled and settled in the nearby city of Umm al-Fahm.