The concept of a sanctuary city dates back millennia, whereas sanctuary cities have been associated with the moral traditions of Hinduism, Buddhism, Judaism, Christianity, Islam, Baha`i and Sikhism, providing refuge and protection variously from capital punishment for unintended manslaughter, persecution, vendetta, violence or other forms of injustice. Historically, some sanctuary cities also were market centers in which foreigners, travelers and traders could circulate without threat of violence or crime committed against them.

Currently, a sanctuary city is a municipality or other local government or administration that welcomes refugees and immigrants regardless of their official immigration or residency status that the state’s central authorities determine. The contemporary designation of sanctuary city has no precise legal definition, but generally applies to administrations that do not use municipal funds or resources to enforce national immigration laws. Such a policy can be set out expressly in a law or other ordinance (de jure), or observed only in practice (de facto). A sanctuary city (or county, or state) policy may forbid its police and/or municipal employees to inquire about a person`s immigration status, or share such information with immigration enforcement agencies as a measure to ensure that all inhabitants may benefit from municipal services, public spaces and exercise their human rights.