Islam is the second largest non Christian religion in the United States after Judaism.
From the 1880s to 1914, several thousand Muslims immigrated to the United States from the Ottoman Empire, and from parts of South Asia; they did not form distinctive settlements, and probably most assimilated into the wider society.
Once very small, the Muslim population of the US increased greatly in the 20th century, with much of the growth driven by rising immigration and conversion, and a comparatively high birth rate. In 2005, more people from Islamic countries became legal permanent United States residents — nearly 96,000 — than in any year in the previous two decades.
American Muslims come from various backgrounds, and are one of the most racially diverse religious group in the United States according to a 2009 Gallup poll. Native-born American Muslims are mainly African Americans who make up 24% of the total Muslim population. Many of these have converted to Islam during the last seventy years. Conversion to Islam in prison, and in large urban areas has also contributed to its growth over the years. South Asian immigrants (from India, Pakistan and Bangladesh) make up 26% of the Muslim population, and Arabs make up 26% of the population. The remaining 24% percent is from other groups.
Muslims in the United States have increasingly contributed to American culture; there are various Muslim comedy groups, rap groups, Scout troops and magazines, and Muslims have been vocal in other forms of media as well.
Within the Muslim community in the United States there exist a number of different traditions. As in the rest of the world, the Sunni Muslims are in the majority. Shia Muslims, especially those in the Iranian immigrant community, are also active in community affairs. All four major schools of Islamic jurisprudence (fiqh) are found among the Sunni community. Some Muslims in the U.S. are also adherents of certain global movements within Islam such as the Salafi, the Muslim Brotherhood, the Gulen Movement, and the Tablighi Jamaat.
Mosques are usually explicitly Sunni or Shia. There are 1,209 mosques in the United States and the nation's largest mosque, the Islamic Center of America, is in Dearborn, Michigan. It caters mainly to the Shi'a Muslim congregation; however, all Muslims may attend this mosque. It was rebuilt in 2005 to accommodate over 3,000 people for the increasing Muslim population in the region.
There is no accurate count of the number of Muslims in the United States, as the U.S. Census Bureau does not collect data on religious identification. There is an ongoing debate as to the true size of the Muslim population in the US.