The 100-Mile Border Zone: Where CBP Can Stop You Without a Warrant

Immigration attorney Charles Kuck warned about a zone most people do not know they live in. Federal regulations give Customs and Border Protection extra authority within 100 miles of any external U.S. boundary: the Mexican and Canadian borders and the coasts.

That is the blunt version, and it overstates it slightly. The Fourth Amendment does not switch off, but the rules are looser here. The “100 air miles” figure comes from 8 CFR 287.1, which defines the “reasonable distance” for the questioning and warrantless-arrest powers Congress gave immigration officers in 8 U.S.C. § 1357. Courts have upheld fixed CBP checkpoints in this zone and allow roving patrols to stop a vehicle on reasonable suspicion, a far lower bar than the warrant you can demand at your front door. The zone covers a huge share of the country, including most major cities.

Kuck pointed to reports of emergency-room doctors with work permits but no underlying status being arrested by CBP in the zone. The practical takeaway is the same discipline that applies everywhere now, just with less margin: carry your documents, know that a checkpoint stop is not the same as a home entry, and if you have no status, be extra cautious about routine travel near the border. It pairs with knowing your rights when ICE comes to the door, who can safely fly domestically, and, for recent entrants, the two-year proof-of-presence line for expedited removal.