|Regions with significant populations|
|Islam (Sunni, Salafiyyah)|
|Related ethnic groups|
|Dir, Darod, Hawiye, Rahanweyn, and other Somali people|
The Isaaq (also Isaq, Ishaak) (Somali: Reer Sheik Isaxaaq, Arabic: إسحاق) are one of the main clans of the Somali people. Members principally live in the northwestern Somaliland region of Somalia, Djibouti and Ogadenia.
According to early Islamic books and Somali tradition, the Isaaq clan was founded in the 12th or 13th century with the arrival of Shaykh Ishaq ibn Ahmad al-Hashimi from Arabia, a descendant of the Islamic prophet Muhammad's cousin Ali ibn Abi Talib . He settled in the coastal town of Maydh in modern-day northernwestern Somalia, where he married into the local Dir clan.
The noted explorer and imperialist, Richard Burton, provided a written account of his interactions with and the commonly understood history of the Issaq clan during his exploration of the region in the early 1850s. Concerning the migration of Sh. Issaq (spelled by Burton as Ishak) Burton states that:
"The last and most important Arab immigration took place about fifteen generations or 450 years ago, when the Sherif Ishak bin Ahmed left his native country hadramaut, and, with forty-four saints, before mentioned, landed on Makhar,—the windward coast extending from Karam Harbour to Cape Guardafui. At the town of Met, near Burnt Island, where his tomb still exists, he became the father of all the gentle blood and the only certain descent in the Somali country: by Magaden, a free woman, he had Gerhajis, Awal, and Arab; and by a slave or slaves, Jailah, Sambur, and Rambad. Hence the great clans, Habr Gerhajis and Awal, who prefer the matronymic— Habr signifying a mother,—since, according to their dictum, no man knows who may be his sire. These increased and multiplied by connection and affiliation to such an extent that about 300 years ago they drove their progenitors, the Galla, from Berberah, and gradually encroached upon them, till they intrenched themselves in the Highlands of Harar" 
There are also numerous existing hagiologies in Arabic which describe Sheikh Isaaq's travels, works and overall life in northern Somalia, as well as his movements in Arabia before his arrival. Besides historical sources, one of the more recent printed biographies of Sheikh Isaaq is the Amjaad of Sheikh Husseen bin Ahmed Darwiish al-Isaaqi as-Soomaali, which was printed in Aden in 1955.
The shortage of verifiable historical record in this area has created a substantial debate as to the genealogy of the Issaq clan in the literature. According to I.M. Lewis, other Somalis "regard the Isaaq as lineal descendants of Dir," while the Isaaq claim only matrilineal descent from Dir and agnatic descent from Arabia. Lewis, however, suggests that "the traditions surrounding the origin and advent from Arabia of Sheikhs Daarood and Isaaq have the characters of myth, rather than history, even though there is every reason to believe that one aspect of Somaliland's long contact with Arabia has been the settlement over the centuries of parties of Arab immigrants.… It would appear that the Isaaq have Arabicized their genealogy as a means of acquiring prestige…."
The three major sub-clans of the Isaaq signed treaties with the British in the 1880s pledging them and their successors not to cede or otherwise alienate any part of their lands except to the British, and allowing the British Government to appoint agents who would reside in the territories of the clans. These groups were the Habr Awal, (dated 14 July 1884), the Habr Toljallo (dated 26 December 1884), and the Habr Garhadjis (13 January 1885).
In the Isaaq clan-family, component clans are divided into two uterine divisions, as shown in the genealogy. The first division is between those lineages descended from sons of Sheikh Isaaq by an Ethiopian woman – the Habar Habuusheed – and those descended from sons of Sheikh Isaaq by a woman of the Magaadle clan – the Habar Magaadle. Indeed, most of the largest clans of the clan-family are in fact uterine alliances. This is illustrated in the following structure.
Sheikh Is-haaq Bin Ahmed
1. Habar Habuusheed
- Ahmed (Tol-Ja’lo)
- Ibrahiim (Sanbuur)
- Mahammad (‘Ibraan)
2. Habar Magaadle
There is no clear agreement on the clan and sub-clan structures and many lineages are omitted. The following listing is taken from the World Bank's Conflict in Somalia: Drivers and Dynamics from 2005 and the United Kingdom's Home Office publication, Somalia Assessment 2001.
- Haber Awal
- Sa'ad Muse
- Issa Muse
- Eli muse
- Habr Garhadjis
- Habr Yunis
- Habr Jaalo (var. Habr Toljallo; Haber Geelo)
- Mohamed Abokor
- Muse Abokor
- Samane Abokor
- Ahmad (Toljaalo)
- Haber Awal
One tradition maintains that Isaaq had twin sons: Ahmed or Arap, and Ismail or Gerhajis.
Historical publications on Sheikh Isaaq include:
- Al-Dur Al Muntakhab Fi Alaqab Wal-asab - 12th-century manuscript by unknown author
- Al Casjad Al-Manduum Li-Taariikh Wal-culuum - 12th-century manuscript by Maxamed Hasan Al-Basri (50 pages, Al-Zahiriyah Library, Al-Hamidiyah Souq, Damascus Syria)
- Al-3asjad Al Manduum - by Sharif Ahmed Muhammad Qaasim Al Gheribaani, a Hashimi historian of Yemen (1910)
- Thamrat Al-Mushtaaq Fi Manaaqib/Nasab al-Sheekh/Sayid Is'haaq - by Sharif Aydarus Sharif Ali Al-Aydarus 1947 (d 1347 H.A.); also the author of Bughyat Al-Amaal Fi-Taariikh Al Soomaal
- Adhwaa 3alaa Taariikh Al-Soomaal - by Shariif Maxamed 3aydarus (1932-1999), the ex-mayor of Mogadishu during the 1968 election in Somalia
- Kitaab Fatx Al-Baab Fi Al-Ansaab Wal-Alaqaab - by 3abdialma3alim Ibn Yuusuf
Notable Isaaq people
- Abdirahman Mohamed Abdullahi, Speaker of the House of Representatives of Somaliland and the Chairman of Wadani political party.
- Abdirahman Ahmed Ali Tuur, Last Somali National Movement Chairman and First President of Somaliland.
- Ahmed Mohamed Mohamoud, President of Somaliland, fourth and longest-serving Chairman of the Somali National Movement, and former Chairman of the Kulmiye Party.
- Faysal Ali Warabe, Chairman of the For Justice and Development party of Somaliland (UCID).
- Fowsiyo Yusuf Haji Adan, former Foreign Minister of Somalia and MP in Federal Parliament.
- Hadrawi, poet and philosopher; author of Halkaraan; also known as the "Somali Shakespeare".
- Hussein Arab Isse, the Minister of Defence and the Deputy Prime Minister of Somalia from July 20, 2011 to November 4, 2012.
- Ismail Ali Abokor, former Vice-President of the Somali Democratic Republic
- Mo Farah, Somali-British long-distance runner, gold medallist at the London 2012 Olympics in the 10,000 metres, giving Britain its first-ever Olympic gold medal victory in the event.
- Mohamed Hasan Abdullahi, Chief of Staff of Somaliland Armed Forces.
- Mohamed Omar Arte, Deputy Prime Minister of Somalia.
- Muhammad Haji Ibrahim Egal, former Prime Minister of Somalia; former President of Somaliland.
- Umar Arteh Ghalib, former Prime Minister of Somalia from January 24, 1991 to May 1993, former President of UN Security Council, teacher and poet.
- Rima Berns McGown, Muslims in the diaspora, (University of Toronto Press: 1999), pp. 27–28
- I.M. Lewis, A Modern History of the Somali, fourth edition (Oxford: James Currey, 2002), p. 22
- Burton, Richard. First Footsteps in East Africa. pp. 53–4. ISBN 9781508616993. Retrieved 16 February 2016.
- Roland Anthony Oliver, J. D. Fage, Journal of African history, Volume 3 (Cambridge University Press.: 1962), p.45
- I. M. Lewis, A pastoral democracy: a study of pastoralism and politics among the Northern Somali of the Horn of Africa, (LIT Verlag Münster: 1999), p.131.
- Lewis, I.M. A Pastoral Democracy: A Study of Pastoralism and Politics Among the Northern Somali of the Horn of Africa. Transaction Publishers. p. 142. ISBN 9783825830847. Retrieved 23 September 2015.
- Lewis, Ioan. M. (1994). Blood and Bone: The Call of Kinship in Somali Society. Larwenceville, NJ: The Red Sea Press Inc. pp. 104–105. ISBN 9780932415936. Retrieved 23 September 2015.
- I.M. Lewis, Peoples of the Horn of Africa: Somali, Afar, and Saho, Issue 1, (International African Institute: 1955), pp. 18-19
- D. J. Latham Brown (1956). "The Ethiopia-Somaliland Frontier Dispute". International and Comparative Law Quarterly 5 (2): 245–264. doi:10.1093/iclqaj/5.2.245. JSTOR 755848.
- I. M. Lewis, A pastoral democracy: a study of pastoralism and politics among the Northern Somali of the Horn of Africa, (LIT Verlag Münster: 1999), p.156.
- I. M. Lewis, A pastoral democracy: a study of pastoralism and politics among the Northern Somali of the Horn of Africa, (LIT Verlag Münster: 1999), p. 157.
- Worldbank, Conflict in Somalia: Drivers and Dynamics, January 2005, Appendix 2, Lineage Charts, p. 55 Figure A-1
- Country Information and Policy Unit, Home Office, Great Britain, Somalia Assessment 2001, Annex B: Somali Clan Structure, p. 43
- Laurence, Margaret (1970). A Tree for Poverty: Somali Poetry and Prose. Hamilton: McMaster University. p. 145. ISBN 1-55022-177-9.
Then Magado, the wife of Ishaak, bore him twin sons, and their names were Ahmed, nick-named Arap, and Ismail, nick-named Gerhajis.
- Islam in Somali History Fact and Fiction revisited , the Arab Factor
- Mohamed Yusuf Hassan, Roberto Balducci (ed.) (1993). Somalia: le radici del futuro. Il passaggio. p. 33. Retrieved 22 September 2014.