What does it mean when a city is an immigrant sanctuary?

What are sanctuary policies? Sanctuary policies first came into popularity with the 2010 passage of AZ state law SB 287g, which allows local police to call ICE whenever they encounter a person whom they believe does not have lawful immigration status. By involving local police in immigration enforcement, many people become caught up in the deportation system who would not have otherwise. As a result, immigrants became afraid to call police even when they were victimized, afraid to cooperate with police or go anyplace where police may be.

Cities across the country, from Austin, to Boulder, to New Orleans, to Cincinnati, have decided to limit how their local police get involved with enforcing immigration laws. The general theme of a sanctuary city is that the feds cannot force a local government to help ICE enforce federal immigration laws and that participation should be voluntary and determined locally.

The Trump admin has demonized sanctuary cities but contrary to his rhetoric, sanctuary cities do not hide immigrants from ICE. Nor do they shield them from deportation. They simply limit how local police can assist in the deportation process, which is ICE's role.

See the American Immigration Council’s summary for more info:

https://www.americanimmigrationcouncil.org/research/sanctuary-policies-overview