The Baharna (Arabic: بحراني ، بحارنة) are an ethnoreligious group whom mainly inhabit the historical region of Eastern Arabia. They are regarded by some scholars to be the original inhabitants of the Bahrain archipelago. Most Shi'i Bahraini citizens are ethnic Bahrana. Regions with most of the population are in Eastern Arabia, Bahrain, Qatif, al-Hasa, Qatar, United Arab Emirates, Oman, Iran, Iraq, United Kingdom and the United States
The origin of Baharna is uncertain; there are different theories regarding their origins. Several Western scholars believe the Baharna originate from Bahrain's pre-Islamic population which consisted of partially-Christianized Arabs, Persian Zoroastrians, Jews and Aramaic-speaking agriculturalists. According to one historian, Arab settlements in Bahrain may have begun around 300 B.C. and control of the island was maintained by the Rabyah tribe, who converted to Islam in 630 A.D. One theory claims the Baharna "immigrated to Bahrain during the Umayyad and Abbasid Caliphates from different parts of the Muslim world."
There are many gaps and inconsistencies in the genealogies of those claiming descent from the Banu Abdul Qays in Bahrain, therefore Baharna are probably descendants of an ethnically-mixed population. Bahraini society has traditionally divided itself into three genealogical categories in order: ansab (clear genealogies), la ansab (unclear genealogies) and bani khudair (foreigner). Baharna were "la ansab" because they have uncertain ancestry.