"Sanctuary state" is a phrase that suggests more than the law delivers. In California it describes a specific statute with specific limits, and one of those limits is large: it does not cover the state prison system.

What the statute actually says

The California Values Act, passed as SB 54 in 2017, restricts how state and local law enforcement may participate in federal immigration enforcement. It bars agencies from using their funds or personnel to investigate, detain or arrest people for immigration purposes, and it prevents holding someone on an immigration detainer alone. It carves out exceptions for people convicted of certain serious or violent offenses.

Those restrictions apply to police departments and sheriff's offices. They were not written to cover the California Department of Corrections and Rehabilitation, and the statute did not include the state prison system, according to The Marshall Project's reporting. State law instead directs prison authorities to identify people subject to deportation and to coordinate custody transfers with federal immigration agents.

That is not a loophole discovered by federal officials. It is how the law was drafted.

The scale

California has transferred more than 18,000 people from state prisons to ICE custody since 2015. The share of people with detainers whom ICE actually collects has risen over that period, from a low of about 72 percent in 2022 to roughly 88 percent more recently.

CalMatters reported that more than 9,000 transfers have occurred since Gov. Gavin Newsom took office in 2019.

How a transfer happens

ICE issues a detainer, a request that someone be held for transfer. A detainer is a request rather than a judicial warrant, and it is not mandatory.

Two details from the reporting are worth stating plainly because they are where the discretion lives. CDCR policy permits moving a scheduled release date earlier in order to hand someone to ICE. And an ACLU lawsuit alleges the department has placed "potential holds" on people based on name, accent or appearance, an allegation the state has not conceded.

Separately, and regardless of any sanctuary provision, fingerprints taken at booking flow to federal databases. That channel is automatic and does not depend on any officer's cooperation, which is why sanctuary rules constrain assistance without making a jurisdiction invisible to federal enforcement.

The arguments

Supporters of the current arrangement frame it as a division of labor: the state does not deputize local police as immigration agents, but it also does not obstruct removal of people who have completed sentences for serious crimes. Newsom's office, asked about the practice, pointed to a broader commitment to "a justice system that emphasizes rehabilitation, second chances, and giving people the opportunity to turn their lives around."

Critics call it double punishment. Their argument is that a person serves the sentence a court imposed, becomes eligible for release, and is then delivered into a separate detention system and often removed from the country and from family. Advocates quoted in the reporting also raise consent and comprehension problems, including literacy barriers around the forms involved.

There is a third position that gets less attention in California coverage and belongs here: critics who argue sanctuary laws already go too far, and that any limit on cooperation with federal immigration enforcement obstructs removals the federal government is entitled to carry out. On that view the prison carve-out is not a contradiction but the minimum the state should be doing.

Why the distinction matters here

Los Angeles County holds the largest immigrant population in the country, and the practical question for a family is narrow: which agency has custody of a relative, and what rules bind it.

The answer differs by stage. A city police department operates under one set of constraints, a county jail under another, and a state prison under a third that permits the coordination the other two largely forbid. "Sanctuary" is not one status but several, and it is also not uniform across the country: as the American Immigration Council notes, the term has no fixed legal definition and covers a wide range of local policies.

Anyone relying on the label alone, in either direction, is likely to be surprised by what it does.