The Isaaq (also Ishaak, Isaac) (Reer Sheekh Isxaaq, is an ethnic group in Somaliland. It is one of the major tribes in the Horn of Africa, with a large and densely populated traditional territories.
The Isaaq people claim descent from Sheikh Ishaaq bin Ahmed, an Islamic scholar who traveled to Somaliland in the 12th or 13th century and married into the local Dir clan.
Somali genealogical tradition places the origin of the Isaaq tribe in the 12th or 13th century with the arrival of the Sheikh Ishaaq Bin Ahmed (Sheikh Ishaaq) from Arabia. Sheikh Ishaaq purportedly settled in the coastal town of Maydh in modern-day northeastern Somaliland, where he married into the local Magaadle clan. Some modern Arabic hagiographies also claim that Sheikh Ishaaq was a descendant of Ali ibn Abi Talib, the cousin and son-in-law of the prophet Muhammad.
There are also numerous existing hagiographies in Arabic which describe Sheikh Ishaaq's travels, works and overall life in modern Somaliland, as well as his movements in Arabia before his arrival. Besides historical sources, one of the more recent printed biographies of Sheikh Ishaaq is the Amjaad of Sheikh Husseen bin Ahmed Darwiish al-Isaaqi as-Soomaali, which was printed in Aden in 1955.
Sheikh Ishaaq's tomb is in Maydh, and is the scene of frequent pilgrimages. Sheikh Ishaaq's mawlid (birthday) is also celebrated every Thursday with a public reading of his manaaqib (a collection of glorious deeds). His Siyaara or pilgrimage is performed annually both within Somaliland and in the diaspora particularly in the Middle East among Isaaq expatriates.
The dialect of the Somali language that the Isaaq speak has the highest prestige of any other Somali dialect.
The Isaaq have a very wide and densely populated traditional territory and make up 80% of Somaliland's population, and live in all of its six regions (Awdal, Marodi Jeh, Togdheer, Sahil, Sanaag and Sool). The Isaaq have large settlements in the Somali Region of Ethiopia, mainly on the eastern side of Somali Region also known as the Hawd and formerly Reserve Area which is mainly inhabited by the Isaaq residents.