Immigration Detainers and Warrants

The County of San Mateo has an ordinance prohibiting cooperation with immigration authorities. The Sheriff’s Office follows the County ordinance and state law, and will not hold, detain, house, transfer, or otherwise facilitate the arrest of any person unless pursuant to a judicial warrant or otherwise required by federal or state statute, regulation, or court decision.

In compliance with the County ordinance, the Sheriff’s Office will publish quarterly reports on this website detailing the number of immigration detainer requests and warrants received from immigration authorities beginning Jan. 1, 2026.

DateYearImmigration Detainers ReceivedNumber of Detainers Acted UponJudicial Warrants or Judicial Bookings Received **Judicial Warrants or Judicial Bookings Acted Upon **
January2025*000
February2025*000
March202570000
April202582000
May2025107000
June2025111011
July2025132000
August202591000
September2025112000
October2025106000
November202567000
December202591000
January202670000
February202642011
Totals 1081022

* Information was not collected prior to March 2025  
** This is a warrant for the arrest of a person signed by a state or federal judge (not an immigration judge) and is legally required to be acted upon.