Since 9/11, the Number of Immigrants from the Muslim World Has Grown by 1.8 Million

As the 25th anniversary of the September 11, 2001, attacks approaches, some may wonder if increased vetting or possible distrust of Muslims in the United States caused fewer people from the Islamic world to immigrate here. An analysis of Census Bureau data shows that the immigrant population (also called the foreign-born) from predominantly Muslim countries has more than doubled since 2001.¹ Not all immigrants from these countries are Muslims. (The Census Bureau does not ask about religion.) Nevertheless, the data indicate that the U.S. did not fundamentally change immigration policy after September 11th, nor does the desire of many people in the Muslim world to settle here seem to have changed much. As a result, the number of immigrants from these countries has soared.

Key Findings:

• The number of immigrants — including naturalized citizens, legal permanent residents, long-term temporary visitors, and illegal immigrants — from the Muslim world increased from 1.7 million in 2001 to 3.4 million in 2024. This represents the net increase — new arrivals minus emigration and natural mortality.²
• Immigrants from predominantly Muslim countries increased by 103 percent from 2001 to 2024. This is much faster than the growth in the overall foreign-born population (58 percent) and is nearly seven times faster than for the overall U.S.-born population. (See Figure 1.)
• The decision to admit large numbers of people from Afghanistan after the U.S. withdrawal caused the population of Afghan immigrants to nearly double from 2020 to 2024, but Afghans accounted for only a quarter of the total increase from the Islamic world over this time period.
• Prior research indicates that 10 to 20 percent of immigrants from majority-Muslim countries may be illegal immigrants — lower than the 25 to 30 percent share for the overall foreign-born.³ The rapid increase in immigrants from the Islamic world overwhelmingly reflects legal immigration policies.
• Many top immigrant-sending countries in the Muslim world have hostile relations with the United States or struggle with powerful terrorist movements. From 2001 to 2024, the immigrant population increased by 202,000 (476 percent) for Afghanistan, 201,000 (93 percent) for Pakistan, 119,000 (41 percent) for Iran, 65,000 (109 percent) for Syria, 66,000 (416 percent) for Yemen, and 45,000 (87 percent) for Somalia.
• In addition to immigrants from majority-Muslim countries, there are 1.9 million U.S.-born individuals with parent(s) from such countries. The total number of immigrants from the Muslim world plus their U.S.-born offspring was 5.4 million in 2024, compared to 2.5 million in 2001 — a 118 percent increase.⁴
• Assuming that recent trends continue, the number of immigrants from majority-Muslim countries and their U.S.-born offspring will nearly double to 10.4 million by 2050.⁵ (See Figure 2.)