Frontier settlements in the United States often lacked established law enforcement agencies and, instead, exercised summary justice through vigilantes. Western pioneers punished murder, rape, horse thievery, and other capital crimes by resorting to lynching.

Even before the American Civil War, many lynchings took place in the southern states. At first most of the victims were white, although the violence usually involved abolitionists or others who worked to end the system of slavery. After the war lynching became a weapon against the black people. During the period of Reconstruction, despite the existence of legal and judicial systems, it was practiced in the South, primarily by the Ku Klux Klan. Often blacks were lynched because they were presumed to have committed crimes against white people. Since 1882, when records of lynchings began to be kept, most have occurred in the southern states; after 1886 the number of black victims annually exceeded the number of white victims.

Georgia and Mississippi have had the largest totals of lynchings; in the six New England states none has occurred. Since 1882 more than 4700 persons have been lynched, and the majority of them were black. The largest number of lynchings in any one year was 230 in 1892. Since the end of World War I, lynching has declined considerably. In the 1960s, however, several persons attempting to secure civil rights for blacks in the South met death through the actions of lynch mobs.