In the context of racism in the United States, racism against African Americans dates back to the colonial era, and continues to be a persistent issue in American society in the 21st century.

From the arrival of the first Africans in early colonial times until after the American Civil War, most African Americans were enslaved. Even free African Americans have faced restrictions on their political, social, and economic freedoms, being subjected to lynchings, segregation, Black Codes, Jim Crow laws, and other forms of discrimination, both before and after the Civil War. Thanks to the civil rights movement, formal racial discrimination was gradually outlawed by the federal government and came to be perceived as socially and morally unacceptable by large elements of American society. Despite this, racism against Black Americans remains in the U.S., as does socioeconomic inequality between black and white Americans. In 1863, two years prior to emancipation, Black people owned 0.5 percent of the national wealth, while in 2019 it is just over 1.5 percent.

In recent years research has uncovered extensive evidence of racial discrimination in various sectors of modern U.S. society, including the criminal justice system, businesses, the economy, housing, health care, the media, and politics. In the view of the United Nations and the US Human Rights Network, "discrimination in the United States permeates all aspects of life and extends to all communities of color."

The Naturalization Act of 1790 set the first uniform rules for the granting of United States citizenship by naturalization, which limited naturalization to "free white person[s]", thus excluding from citizenship Native Americans, indentured servants, slaves, free Blacks, and later Asians. Citizenship and the lack of it had special impact on various legal and political rights, most notably suffrage rights at both the federal and state level, as well as the right to hold certain government offices, jury duty, military service, and many other activities, besides access to government assistance and services. The second Militia Act of 1792 also provided for the conscription of every "free able-bodied white male citizen". Tennessee's 1834 Constitution included a provision: "the free white men of this State have a right to Keep and bear arms for their common defense."

Citizenship, however, did not guarantee any particular rights, such as the right to vote. Black Americans, for example, who gained formal U.S. citizenship by 1870, were soon disenfranchised. For instance, after 1890, less than 9,000 of Mississippi's 147,000 eligible African-American voters were registered to vote, or about 6%. Louisiana went from 130,000 registered African-American voters in 1896 to 1,342 in 1904 (about a 99% decrease).^{[citation needed]} They were also subjected to Black Codes and discriminated against in the Southern states by Jim Crow laws. Voter suppression efforts around the country, though mainly motivated by political considerations, often effectively disproportionately affect African Americans and other minorities. In 2016, one in 13 African-Americans of voting age was disenfranchised, more than four times greater than that of non-African-Americans. Over 7.4% of adult African-Americans were disenfranchised compared to 1.8% of non-African-Americans. Felony disenfranchisement in Florida disqualifies over 10% of its citizens for life and over 23% of its African-American citizens.

Slavery, as a form of forced labor, has existed in many cultures, dating back to early human civilizations. Slavery is not inherently racial per se. In the United States, however, slavery, having been established in the colonial era, became racialized by the time of the American Revolution (1775–1783), when slavery was widely institutionalized as a racial caste system which was based on African ancestry and skin color.

The Atlantic slave trade prospered, with more than 470,000 persons forcibly transported from Africa between 1626 and 1860 to what is now the United States. Prior to the Civil War, eight serving presidents were slaveholders, and slavery was protected by the U.S. Constitution. Creating wealth for the White elite, approximately one in four Southern families held Black people in slavery prior to the Civil War. According to the 1860 U.S. census, there were about 385,000 slave owners out of a White population of approximately 7 million in the slave states. White European Americans who participated in the slave industry sought to justify their economic exploitation of Black people by creating a "scientific" theory of White superiority and Black inferiority. Thomas Jefferson, a slave owner himself, called for science to determine the obvious "inferiority" of Black people that is regarded as "an extremely important stage in the evolution of scientific racism." He concluded that Black people were "inferior to the whites in the endowments of body and mind."

Groups of armed White men, who were called slave patrols, were formed to monitor enslaved Black people. First established in South Carolina in 1704 and later established in other slave states, their function was to police slaves, especially runaways. Slave owners feared that slaves might organize revolts or rebellions, so state militias were formed to provide a military command structure and discipline within the slave patrols so they could be used to detect, encounter, and crush any organized slave meetings which might lead to revolts or rebellions.