An immigration detainer is an ICE request to another law-enforcement agency concerning a person in that agency’s custody. It can request notice of release and temporary continued custody so ICE can assume custody. It is not a criminal conviction or a final determination that the person must be deported.
A detainer is not a judge’s arrest warrant
The detainer regulation describes an administrative request. A detainer and an administrative immigration warrant differ from a judicial warrant signed by a judge. Which documents exist and what independent legal authority supports detention are important questions. [1]
Local agencies’ responses can depend on federal constitutional decisions, state law, local rules, and the facts supporting the request. Do not assume every jail must honor every detainer merely because it comes from a federal agency.
Understand which 48-hour rule applies
The regulation describes temporary custody not exceeding 48 hours, excluding Saturdays, Sundays, and holidays. Published ICE I-247A materials use a request for no more than 48 hours beyond otherwise-required release; forms and policies can describe a narrower requested period. Review the actual form, release-eligibility time, and controlling legal requirements rather than automatically adding a weekend to every hold. [1][2]
The relevant starting point generally concerns when the person would otherwise be released from the original custody. A person still held on an independent criminal basis presents a different calculation from someone whose sole remaining restraint is the immigration request.
What to obtain quickly
- The detainer and any accompanying warrant.
- The person’s criminal release order and release-eligibility time.
- The stated immigration basis and identifying information.
- Records of when ICE was notified and whether custody transferred.
A detainer can complicate bail decisions without deciding the criminal case. Immigration bond eligibility is another issue and may be limited by the person’s circumstances.
Compare removal risks for green card holders and immigration court jurisdiction. If a hold appears to exceed the lawful period or names the wrong person, counsel should address the actual custody basis promptly. Paying criminal bail alone should not be assumed either to guarantee release or to resolve the immigration matter.
Primary sources
Sources checked: October 31, 2026.