Sheriff’s departments across the Inland Empire are transferring jail inmates to U.S. Immigration and Customs Enforcement custody at rates higher than many other counties in California, according to a newly released analysis examining immigration detainer activity statewide.
The report focuses on immigration detainers, which are requests made by ICE asking local law enforcement agencies to notify federal officials before releasing a deportable immigrant from custody. Detainers also request that inmates be held for up to 48 additional hours so ICE agents have time to take them into federal custody.
Data compiled for 2025 shows Riverside County transferred 158 out of 1,380 inmates with immigration detainers into ICE custody, amounting to an 11.4% transfer rate. San Bernardino County transferred 180 out of 1,674 detainees, or 10.8%. Both counties ranked above the statewide average of 8.49%, according to the analysis.
By comparison, Los Angeles County transferred 4.6% of inmates with immigration detainers, while Orange County transferred 7.6%. Across California, 2,077 inmates out of 24,438 people flagged with immigration detainers were ultimately transferred to ICE custody during 2025.
The findings were assembled by Keith Maben, a sophomore at Claremont McKenna College and head of the Immigration Task Force at the Mgrublian Center for Human Rights. Maben said Riverside and San Bernardino counties stood out because their transfer rates were noticeably higher than California’s average.
“San Bernardino and Riverside County were on the higher end of enforcement data,” Maben said. “Both of them had results where about 10 to 12% of these detainees actually resulted in people going into ICE custody.”
Maben noted that while the percentage differences may appear small on paper, the contrast becomes clearer when compared to counties such as Santa Clara County, where less than 1% of detainees with immigration detainers were transferred to ICE.
The report also found a pattern between transfer rates and political leanings across California counties. Counties with more conservative voter bases and sheriffs tended to report higher levels of cooperation with federal immigration authorities.
Among the counties with the highest transfer percentages were Imperial County at 33.7%, Kings County at 29.1%, Santa Barbara County at 24.9%, Tuolumne County at 24.3%, and Del Norte County at 22.2%. Riverside County ranked 12th statewide, while San Bernardino County ranked 13th.
Maben said his research examined how sheriff’s departments interpret California’s Senate Bill 54, also known as the California Values Act, which limits cooperation between local law enforcement agencies and federal immigration authorities.
Through public records requests, the Mgrublian Center obtained documents outlining agreements between Riverside County and federal agencies, including a 2020 memorandum with Homeland Security Investigations and a 2024 agreement with U.S. Border Patrol tied to drug smuggling investigations.
“We found a very strong effect where California sheriffs who tended to cooperate with the federal government or have memorandums of understanding also tended to have higher enforcement data,” Maben said.
One document highlighted in the report was Riverside County’s 2018 ICE Detainer Eligibility Worksheet, which lists 30 serious or violent felonies that may justify notifying ICE before an inmate’s release.
Immigrant rights advocates say the numbers are troubling, though not unexpected. Eddie Torres, policy director for the Inland Coalition for Immigrant Justice, pointed to the presence of the Adelanto ICE Processing Center and the nearby Desert View Annex as a possible reason the Inland Empire sees higher transfer rates.
“When you have a detention center near you, it makes sense you’d have a higher rate of transfers because it makes logistical sense,” Torres said.
The Inland Coalition for Immigrant Justice is part of the Shut Down Adelanto Coalition, a group of organizations pushing to close the Adelanto detention facilities operated by GEO Group. Torres said advocates came close to shutting the facilities down in 2023 before federal officials renewed the contract for another five years.
The discussion around immigration transfers has also become tied to California’s broader political debate over immigration enforcement. Riverside County Sheriff Chad Bianco, who is currently running for governor, has publicly advocated for stronger cooperation between local law enforcement and federal immigration agencies. His campaign platform calls for ending policies such as SB 54 and allowing local law enforcement to work more closely with federal immigration officials in criminal cases involving undocumented immigrants.
In response to questions about the report, Riverside County Sheriff’s Department spokesperson Lt. Deirdre Vickers said the department follows California law and does not exercise discretion beyond the legal requirements outlined in SB 54.
“The Riverside Sheriff’s Office complies with the law,” Vickers said in a written statement. “First, the Sheriff’s Office receives a request for transfers from ICE. The Sheriff’s Office then determines the inmates who meet the requirements under SB 54. Of those inmates, ICE determines which inmates are transferred into their custody.”
The San Bernardino County Sheriff’s Department disputed portions of the data used in the report. Department officials said they received 1,423 ICE notifications in 2025 rather than the 1,674 cited in the analysis, and said only 47 inmates were transferred to ICE custody instead of 180.
Maben acknowledged that some of the data may be imperfect because it was reconstructed through federal public records requests and not reported directly by ICE.
“I think it’s important to take this data with a grain of salt,” Maben said. “It tells us something, but it’s not going to inform the whole story.”
ICE also questioned the accuracy of the Deportation Data Project, which supplied much of the information used in the analysis. In a statement, the agency said its internal systems do not support the project’s numbers and that ICE could not verify the completeness or accuracy of the outside data.
San Bernardino County Sheriff Shannon Dicus argued that restrictions created by SB 54 have shifted immigration enforcement away from county jails and into public spaces. Dicus said allowing transfers to occur inside secure jail facilities would reduce risks to both officers and the public.
“Those in-custody transfers provided a more predictable, secure, and efficient process for law enforcement and reduced risk to the public,” Dicus said in a written statement. “Current law prohibits that level of coordination.”
Los Angeles County officials said their department requires a federal judicial warrant signed by a judge before an inmate can be transferred to ICE custody, in accordance with county policy and California law. Orange County Sheriff Don Barnes also stated publicly that ICE ultimately decides whether to pick up inmates with detainers after their jail commitments end.
Meanwhile, immigrant rights advocates believe immigration enforcement activity will continue increasing throughout 2026 as the federal government expands detention operations nationwide. Torres said advocacy groups are increasingly concerned about what they describe as more tactical immigration enforcement operations occurring in courthouses and other public settings.
Maben’s full report for the Mgrublian Center for Human Rights is expected to be released in the coming weeks.
