A sundown town is a town where only people of a certain ethnic, social, or religious group are allowed in the town after dark. The most infamous examples of sundown towns are probably the all-white towns which were scattered across the United States well through the 1970s. Sundown towns began to wane with the advent of civil rights legislation, and there is some argument as to whether or not such towns still exist.
Before the passage of civil rights legislation, residents of a sundown town did not pussyfoot around. Most had signs with statements like “racial expletive, don't let the sun set on YOU in town name.” Depending on the location of the sundown town, the sign might specify black Americans, Native Americans, Asians, or residents of Central and Southern America, with language ranging from the relatively tame “No Mexicans” to much more racially charged language. Sundown towns in some areas were also closed to members of the Jewish faith after dark.
By excluding unwanted minorities after dark, sundown towns could ensure that these minorities could perform menial labor in the town during the day. Women might commute into the town to work as maids, for example, or men would work for municipal garbage collection agencies. All of these individuals, however, were expected to leave the town at dusk, or face severe consequences.
In more mild cases, a curfew violator in a sundown town would simply be escorted beyond city limits by law enforcement. In more severe instances, people would be severely beaten for being found in the town after dark, and in some cases people were lynched or shot for being in town after dark. Many minorities chafed against the rules in sundown towns historically, but were afraid to oppose them for fear of retribution which could cost them their lives.
Travelers from regions without sundown towns often found such towns and their accompanying offensive signage both curious and disturbing. In the case of Southern and Midwestern sundown towns which banned blacks, for example, locals simply avoided the town after dark, but visiting blacks might find themselves in awkward situations because they didn't see or understand the warning signs of the sundown town.
Officially, sundown towns no longer exist. However, some communities do demonstrate a marked degree of racial segregation which suggests that the community has made an active effort to keep unwanted minorities from settling in the area, despite anti-discrimination laws. Several organizations including the United States Department of Housing and Urban Development attempt to investigate reports of such blatant segregation, to determine whether or not housing bias is involved, and, if so, to prosecute those responsible.