What Are Sanctuary Cities?

States, counties and cities across the U.S. have adopted policies to limit cooperation with immigration agents who seek to deport undocumented immigrants.

About a dozen states and hundreds of cities across the United States consider themselves “sanctuaries” for undocumented immigrants, but there is no universal definition for what constitutes a “sanctuary” jurisdiction.

The term typically refers to states, counties or cities that put some limits on how much they are willing to cooperate with federal agencies’ efforts to deport undocumented immigrants.

Local governments first began adopting sanctuary policies in the 1980s when churches offered refuge to people fleeing civil war in El Salvador. The practice has drawn increased attention over the last decade, as immigration became a bigger issue for voters.

During Donald J. Trump’s first term in office, many Democratic-led jurisdictions affirmed or reinforced their status as sanctuaries. But in recent years, many Democratic-led cities have been overwhelmed with migrants, many of whom were bused there from the southern border by the administration of Gov. Greg Abbott of Texas. That has fueled criticism of the cities’ sanctuary policies, not only from longstanding opponents but also from leaders who once supported the idea.

President Trump and his allies have promised to take a hard line on immigration, and senior officials have made clear that some of the cities that have embraced sanctuary policies would be targeted for enforcement actions.

“Sanctuary jurisdictions aren’t going to stop what we’re going to do,” Thomas D. Homan, Mr. Trump’s new “border czar,” said in an interview with NewsNation in December.