San Mateo County, CA Immigration Policy: Sanctuary Policy Preemption (2026)
Key Facts
- Applies to
- All San Mateo County departments/staff
- Key exception
- Judicial warrant required
- Coyote Point range
- No ICE access without warrant
- Reporting
- Quarterly Sheriff/Probation reports
Summary
County departments and staff are barred from using county resources to assist federal immigration enforcement absent a judicial warrant, under a countywide non-cooperation ordinance.
All County of San Mateo ("County") departments, agencies, commissions, officers, agents, representatives, and employees are prohibited from using County resources, property, personnel, time, labor, or funds to...hold, detain, house, transfer, or otherwise facilitate the arrest of any person in the custody of the San Mateo County Sheriffs Office, Probation Department, or any other County Department, unless pursuant to a judicial warrant (as defined in California Government Code Section 7284.4(i)) or otherwise required by federal or state statute, regulation, or court decision.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 47).
Full Breakdown
Chapter 2.48 of the San Mateo County Ordinance Code bars all county departments, agencies, officers and employees from using county resources, property, personnel, time, labor or funds to assist ICE or other immigration authorities in detaining, transferring or arresting people in county custody, or to share release-date, address or contact information, unless a judicial warrant is presented or federal/state law otherwise requires it. The Sheriff and Chief Probation Officer must also file quarterly public reports on immigration detainer requests received and on any immigration enforcement activity observed in the county.
Violations & Fines
No fine schedule; enforced as internal county policy: county staff who violate it are subject to department discipline, not the public.
Frequently Asked Questions
Does this stop ICE from operating in San Mateo County?
Does it cover cities like Redwood City or San Mateo?
Sources & Official References
Other rules in San Mateo County
California rules heatmap·Compare San Mateo County to another location·View the California immigration policy overview
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