The country has an area of 402,356 square miles and a population of approximately 31 million. Reliable data on religious demography is not available because an official nationwide census has not been conducted in decades. Observers estimate that 80 percent of the population is Sunni Muslim, 19 percent Shi'a Muslim, and other religious groups less than one percent of the population. According to self-estimates by these communities, there are approximately 4,900 Sikh and 1,100 Hindu believers, and more than 400 Baha'is. There is a small, hidden Christian community; estimates on its size range from 500 to 8,000. In addition, there are small numbers of adherents of other religious groups, mostly Buddhist foreigners. There is one known Afghan Jew.
Traditionally, the dominant religion has been Islam, and the sect of Sunni Islam that follows the Hanafi school of religious thought. For the last 200 years, much of the population adhered to Deobandi-influenced Hanafi Sunnism. The Dar-ul-Ulum (Institute of Higher Religious Education) at Deoband is a prominent Asian center of Sunni religious education. Many Afghan Sunni religious scholars have either studied at Dar-ul-Ulum Deoband themselves, or were trained by scholars who had studied there. A sizable minority of Afghans also adhered to orders of Islamic spirituality and mysticism, generally known as Sufism. Sufism centers on orders or brotherhoods (both Sunni and Shi'a) that follow charismatic religious leaders. During the 20th century, influence of the "Wahhabi" form of Islam grew in certain regions.
Members of the same religious groups have traditionally concentrated in certain regions. Some groups were displaced forcibly by kings for internal security reasons or to make agricultural and grazing land available to favored ethnic groups. Sunni Muslim Pashtuns dominate the south and east. The homeland of the Shi'a Hazaras is in the Hazarajat, the mountainous central highland provinces around Bamyan Province. Northeastern provinces traditionally have Ismaili populations. Other areas, including Kabul, the capital, are more heterogeneous and include Sunni, Shi'a, Hindu, Sikh, and Baha'i populations. The northern city of Mazar-e-Sharif includes a mix of Sunnis (including ethnic Pashtuns, Turkmen, Uzbeks, and Tajiks) and Shi'a (Hazaras and Qizilbash) including Shi'a Ismailis.
In the past, small communities of Hindus, Sikhs, Baha'is, Jews, and Christians lived in the country, although most members of these communities emigrated during the years of civil war and Taliban rule. Non-Muslim minorities were estimated to number in the hundreds at the end of Taliban rule. A small population of native Hindus and Sikhs never departed. Since the fall of the Taliban, some members of religious minorities have returned, with many settling in Kabul.
Nuristanis, a small but distinct ethnolinguistic group living in a mountainous eastern region, practiced an ancient polytheistic religion until they converted to Islam in the late 19th century. Some non-Muslim religious practices survive today as folk customs, though the Nuristanis are Muslims.
There are two active gurdwaras (Sikh places of worship) in Kabul, and six Hindu mandirs (temples) in four cities. Two mandirs are located in Kabul. Eighteen others were destroyed or rendered unusable due to looting during wartime.
There is one Christian church and one synagogue. Some citizens who converted to Christianity as refugees have returned. Others may have been born abroad into other religious groups. The Baha'i faith has had followers in the country for approximately 150 years. The community is predominantly based in Kabul, where more than 300 Baha'i members live; another 100 are said to live in other parts of the country.