The U.S. government estimates the population at 39 million (July 2017 estimate). According to 2010 government statistics, the most recent available, 97 percent of the population is Muslim. Shia Muslims, predominantly Arabs but also including Turkmen, Faili (Shia) Kurds, and others, constitute 55 to 60 percent of the population. Sunni Muslims are approximately 40 percent of the population. Of Sunnis, Sunni Kurds constitute 15 percent, Sunni Arabs 24 percent, and Sunni Turkmen the remaining 1 percent. Shia, although predominantly located in the south and east, are the majority in Baghdad and have communities in most parts of the country. Sunnis form the majority in the west, center, and north of the country.
Christian leaders estimate there are fewer than 250,000 Christians remaining in the country, with the largest population – at least 200,000 – living in the Ninewa Plain and the IKR. The Christian population has declined over the past 15 years from a pre-2002 population estimate of between 800,000 and 1.4 million persons. Approximately 67 percent of Christians are Chaldean Catholics (an eastern rite of the Roman Catholic Church), and nearly 20 percent are members of the Assyrian Church of the East. The remainder are Syriac Orthodox, Syriac Catholic, Armenian Catholic, Armenian Apostolic, and Anglican and other Protestants. There are approximately 3,000 evangelical Christians in the IKR.
Yezidi leaders report most of the 600,000-750,000 Yezidis in the country reside in the north, with more than 350,000 still living in camps in the IKR. Estimates of the size of the Sabean-Mandean community vary. According to Sabean-Mandean leaders, 10,000 remain in the country, mainly in the south with small pockets in the IKR and Baghdad. Bahai leaders report fewer than 2,000 members, spread throughout the country in small groups. The Shabaks include about 350,000-400,000 persons, two-thirds to three-fourths of whom are Shia and the rest Sunni; most are located in Ninewa. Armenian leaders report a population of around 7,000. According to Kaka’i (also known as Yarsani) activists, their community has approximately 120,000-150,000 members, traditionally located in the Ninewa Plain; others live in villages southeast of Kirkuk, as well as in Diyala, Erbil, and Karbala. The Jewish representative in the KRG Ministry of Endowment and Religious Affairs (MERA) reports 430 Jewish families reside in the IKR. According to a Baghdad Jewish community leader, there are nine adult members of the local Jewish community.
Due to four years of intensive combat, 5.8 million civilians remained displaced within the country. According to the International Organization for Migration (IOM), by year’s end 3.3 million individuals had returned home, leaving 2.5 million IDPs within the country. Population movements are multi-directional, with some persons fleeing their homes and others returning home. According to the IOM, as of November, approximately 67 percent of the IDP population is Arab Sunni, 8 percent Yezidi, 9 percent Turkmen Shia, 6 percent Kurdish Sunni, 3 percent Arab Shia, 3 percent either Syriac, Chaldean, or Assyrian Christians, 2 percent Shabak Shia, and less than 1 percent Turkmen Sunni, Shabak Sunni, or Kurdish Shia.