Historically in the mid-nineteenth century, Southern Anglo settlers primarily from the southeastern United States crossed the Mississippi River, migrating to Texas.

[13] Roberto R. Treviño, author of The Church in the Barrio: Mexican American Ethno-Catholicism in Houston, said that German Americans "historically played a central role in Houston, far outnumbering other whites such as the British, Irish, Canadians, French, Czechs, Poles, and Scandinavian groups who historically have comprised a smaller part of the city's ethnic mosaic.

In 2004 about 33% of Anglo white people residing in Harris County originated from the Houston area, either by birth or from growing up there as children.

[17] Demographers Max Beauregard and Karl Eschbach, both of University of Houston Center for Public Policy, concluded from their analysis of the 2000 U.S. census that white flight from the city continued to occur in the 1990s.

In the decade prior to the 2000 census, white residents left communities within Houston such as Alief, Aldine, Fondren Southwest, Gulfton, and Sharpstown.

Other communities in Houston that lost large numbers of whites by the 2000 census include Inwood Forest, Northline, Northside, and Spring Branch.

Communities in other parts of Greater Houston that lost large numbers of whites included Channelview, Cloverleaf, Galena Park, and Pasadena.

[18] Lori Rodriguez said, regarding the movement of white people in Greater Houston leading up to the year 2000, "Picture a stone dropped on the urban core and ripples of people spreading from within the Loop to the second-ring suburbs between the Loop and Beltway 8; and then beyond, to the outer-ring settlements and even unincorporated perimeter; Kingwood, The Woodlands, FM 1960.

"[18] In the period between the 1990 and 2000 censuses, the largest growth of non-Hispanic White Americans within Greater Houston occurred in white-majority communities, such as Clear Lake City, Kingwood, northwest Harris County, the FM 1960 corridor, and The Woodlands.

In the same year Karl Eschbach, a University of Texas Medical Branch demographer, said that the number of illegal immigrants in the Houston area was estimated at 400,000, with over 70% being of Mexican descent.

Historically, the city of Houston had a significant African American population,[14] as this area of the state developed cotton plantation agriculture that was dependent on enslaved laborers.

[14] Before being effectively disfranchised by the state legislature imposing payment of a poll tax in 1902, they were politically active and strongly supported Republican Party candidates.

In 1970, 90% of the black people in Houston lived in predominantly African American neighborhoods, reflecting decades of legal, residential segregation.

[25] Since the late 20th century, with changes in social conditions and the burgeoning Houston economy, there has been an increasing New Great Migration of blacks to the South.

Many are college educated and have moved to Houston for its lower cost of living and job opportunities compared to some northern and western cities.

[26] Many of the new professional migrants settle directly in the suburbs, which offer more housing than the city; among them are upper class, majority-black neighborhoods.

[37] American Indian communities have existed in the present-day city and area of Houston prior to European colonization and settlement.

As of 2021[update] tribes represented included the Alabama Coushatta, Choctaw, Comanche, Cherokee, Lipan Apache, Muskogee Creek, Navajo, Ponca, and Tunica Biloxi ethnic groups, with about 68,000 Native Americans in the area as of 2010.

Until Continental Airlines began nonstop flights to Lagos from George Bush Intercontinental Airport in November 2011, many Nigerians had to fly through Europe to travel between Texas and Nigeria.

[55] In 2016 United Airlines, which had merged with Continental, canceled the Lagos route, citing a decline in the energy industry and inability to get currency out of Nigeria.

[57] According to the Migration Policy Institute, 2018 estimates from the U.S. Census Bureau state that 40,000 Houston residents were of recent Nigerian origins.

Houston has TV services catering to area West Africans, including AfrocentrikTV, Afrovibes Entertainment, and Millenium Broadcasting Corporation.

The city has a Polish American church, Our Lady of Czestochowa Roman Catholic Parish in Spring Branch, established in the 1980s.

As of that year, 12 city blocks along Hillcroft Avenue, from Westheimer Road to a point just south of Westpark, contain a Persian business district including shops and restaurants.

[107] Badr stated that as of 2000, about 10% of the Islamic Society of Greater Houston (ISGH) consists of ethnic Arabs, from a variety of Middle East nations.

[112] The South Texas Office of Refugees stated that from 2009 to 2021 11,790 people came from Afghanistan to the Houston area, with 90% of them having Special Immigrant Visas which belonged to Afghans who interpreted for the U.S.

According to the 2022 American Community Survey, the most commonly spoken languages in Houston by people aged 5 years and over (2,149,641 people):[124] According to the Pew Research Center and D Magazine, Houston and its metropolitan area are the third-most religious and Christian area by percentage of population in the United States, and second in Texas behind the Dallas–Fort Worth metroplex.

[128] In the same study by the Pew Research Center, an estimated 20% of Houston-area residents claimed no religious affiliation, compared to about 23% nationwide.

[129] Houston-area residents identifying with other religions (including Islam, Judaism, Buddhism, and Hinduism) collectively made up about 7% of the religious and spiritual population.

But, according to a Rice University Kinder Institute for Urban Research 2013 opinion poll, they were surprisingly liberal on a variety of hot-button social topics, "such as immigration, gun control and equal matrimonial rights for same-sex couples".