Traditionally there have been very few Shias in Algeria, except for those who were around in the Middle Ages, but there are a few native Shias and some converts. Western Algeria was part of Shia Idrisid state when Idris II died in 828 CE. The Fatimid state originated among the Kutama people of Algeria. The dynasty was founded in 909 CE by Abdullah al-Mahdi Billah, who in the late 9th century started a movement among the Kutama Berbers and managed to convert them to Shia Islam. In the Middle Ages local Berber dynasties adopted Shia Islam. Recently, the region have reported an increasing popular interest in Shi'ism.
Following Shia Muslim observance are observed in Algeria:
Arba'een of Imam Hussain
Mawlid an Nabi, the birth of the Prophet Muhammad
Birth of Imam Mahdi
Eid al-Ghadeer, commemorates the appointment of Imam Ali ibn Abi Talib by Prophet Muhammad as his immediate successor
Shia population in Algeria is estimated between half to two percent of the total Muslim population of Algeria, according to Pew Forum it is less than one percent while as per Imam Husayn (as) Encyclopedia the population of Shia in Algeria is around two percent of the total Muslim population of Algeria.