Special Notice / Hearing: None__
Vote Required: Majority
To: Honorable Board of Supervisors
From: Ken Binder, Sheriff’s Office
Subject: Sheriff’s Office report on Immigration Activities
RECOMMENDATION:
title
Accept the Sheriff’s Office Report on Immigration Detainers, pursuant to Chapter 2.48 of Title 2 of the San Mateo County Ordinance Code.
body
BACKGROUND:
On November 14, 2025, the San Mateo County Board of Supervisors adopted an ordinance amending Chapter 2.48 of Title 2 of the San Mateo County Ordinance Code that requires the Sheriff’s Office to provide a written report on immigration activities, including civil immigration detainer requests as well as any communications related to immigration authorities by March 1st, June 1st, September 1st, and December 1st of each year.
DISCUSSION:
The Sheriff’s Office is committed to maintaining public safety and public trust and ensuring transparency within San Mateo County, particularly among immigrant communities.
Definitions:
1. Immigration Detainer is a request from U.S. Immigration and Customs Enforcement (ICE) to a local jail or police department.
What it is:
A notice saying: “If you’re about to release this person, please hold them for up to 48 extra hours so ICE can come pick them up.”
Important:
• It is not a judge’s order.
• It’s an administrative request from a federal immigration agency.
What it means to act on it:
If a jail “acts on” a detainer, they keep the person in custody for up to 48 additional hours after they would otherwise be released, so ICE can take custody.
2. Judicial Warrant is an official order signed by a judge.
What it is:
A judge reviews evidence and formally orders law enforcement to do something specific such as:
• Arrest someone
• Take someone into custody
3. Judicial Booking is taking custody of the person arrested.
The table below represents the number of communications the Sheriff’s Office has received from immigration authorities since January 2025.
|
Date |
Year |
Immigration Detainers Received |
Number of Detainers Acted Upon |
Judicial Warrants or Judicial Bookings Received |
|
|
|
|
|
|
|
January |
2025 |
* |
0 |
0 |
|
February |
2025 |
* |
0 |
0 |
|
March |
2025 |
70 |
0 |
0 |
|
April |
2025 |
82 |
0 |
0 |
|
May |
2025 |
107 |
0 |
0 |
|
June |
2025 |
112 |
0 |
1 |
|
July |
2025 |
132 |
0 |
0 |
|
August |
2025 |
91 |
0 |
0 |
|
September |
2025 |
112 |
0 |
0 |
|
October |
2025 |
106 |
0 |
0 |
|
November |
2025 |
67 |
0 |
0 |
|
December |
2025 |
91 |
0 |
0 |
|
January |
2026 |
70 |
0 |
0 |
|
February |
2026 |
56 |
0 |
1 |
|
March |
2026 |
89 |
0 |
0 |
|
April |
2026 |
102 |
0 |
1 |
|
May |
2026 |
117 |
0 |
1 |
|
June |
2026 |
58 |
0 |
0 |
|
July |
2026 |
57 |
0 |
0 |
|
August |
2026 |
89 |
0 |
0 |
|
September |
2026 |
58 |
0 |
0 |
|
Totals |
|
1666 |
0 |
4 |
* Information was not collected prior to March 2025
During the period of June 1, 2026 through September 30, 2026, the San Mateo County Sheriff’s Office received a total of 262 immigration detainers, including 58 in June, 57 in July, 89 in August, and 58 in September. No immigration detainers received during this period were acted upon. Additionally, there were no bookings associated with judicial immigration warrants during this period.
COMMUNITY IMPACT:
The Sheriff’s Office serves adults impacted by the justice system, including immigrants, minorities, youth of color, low-income families.
Through this report, the Sheriff’s Office strengthens its commitment to serving its clients regardless of their immigration status.
FISCAL IMPACT:
There is no fiscal impact related to this report.