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Key Facts
- National overview: Federal law defines an immigration detainer as a request that another law enforcement agency notify DHS before release so DHS can arrange to assume custody for arrest and removal.
- National overview: The detainer regulation allows an authorized immigration officer to issue Form I-247 to other federal, state, or local law enforcement agencies.
- National overview: The regulation ties detainer custody requests to a limit of no more than 48 hours excluding Saturdays, Sundays, and holidays.
- National overview: The eCFR states that a detainer generally creates no fiscal obligation for DHS until DHS actually assumes custody.
- National overview: DHS OIG described Secure Communities as relying on automated information sharing between DHS IDENT and the FBI IAFIS.
- National overview: DHS OIG reported that officers could request local detention for up to 48 hours excluding holidays and weekends and that many interviewed jurisdictions reported no incarceration costs attributable to Secure Communities activation.
- National overview: BJS defines the imprisonment rate as the number of prisoners under state or federal jurisdiction with sentences of more than 1 year per 100,000 U.S. residents.
- National overview: BJS reported that Hispanic males were imprisoned at 2 to 3 times the rate of white males in 2011, but the reviewed official sources do not provide a causal finding that immigration enforcement increases caused the disparity.
Last reviewed: May 2026. Legal rules, forms, deadlines, and procedures can change by jurisdiction, agency, and court system.
The 2012 legacy narrative that frames Hispanic incarceration rate increases as “driven by” immigration enforcement mixes two different kinds of official information: (1) federal immigration custody coordination tools that affect who is held briefly in a local jail while DHS can take custody, and (2) federal statistical measures of who ends up in prison under state and federal jurisdiction for sentences longer than one year.
To sort the confusion, it helps to start with the term “detainer.” Federal regulations describe a detainer as a request for notice and coordination, not as a final criminal disposition. Under the eCFR, a detainer is issued so that DHS can arrange to assume custody when immediate physical custody is impracticable or impossible, and it serves a specific arrest-and-removal purpose.
An immigration detainer under the regulation is tied to the federal Form I-247 framework. The eCFR states that any authorized immigration officer may issue a Form I-247 detainer to other federal, state, or local law enforcement agencies and that the detainer advises that DHS seeks custody of an alien currently held by the receiving agency for arresting and removing the alien.
The regulation also limits how long the holding agency retains the person. The eCFR requires that, when DHS issues a detainer under this section, the holding criminal justice agency must maintain custody for no more than 48 hours excluding Saturdays, Sundays, and holidays to permit DHS to assume custody, and it treats custody timing and cost responsibility as part of the detainer framework.
ICE Form I-247A mirrors that timing concept in form language. The form asks the holding agency to maintain custody for a period “NOT TO EXCEED 48 HOURS beyond the time when he/she would otherwise have been released from your custody to allow DHS to assume custody,” and the regulation adds that DHS generally incurs no fiscal obligation on the detainer until it actually assumes custody.
Federal immigration detention authority provides the broader legal background for these custody events. For example, 8 U.S.C. § 1226 contemplates detention pending a decision on whether an alien is to be removed, and 8 U.S.C. § 1231 directs detention during the removal period after removal is ordered.
In practice, detainers operate in a custody space shared with state and local systems because the holding agency is often a state or local jail or similar facility. That is why state courts and federal-state interactions matter when detainers are discussed, since local custody decisions determine what DHS can coordinate for the federal removal process, even though the detainer framework is federal.
Secure Communities is one federal mechanism that DHS OIG described as operating through information-sharing and custody coordination. In its oversight report, DHS OIG described Secure Communities as using automated information sharing between DHS IDENT and the FBI IAFIS, and it described a process step in which officers could request local detention for up to 48 hours excluding holidays and weekends to allow ICE to take custody.
DHS OIG also reported local cost perceptions from interviews. In interviews with 37 local jurisdictions, DHS OIG reported that 31 (84%) jurisdictions said they did not incur incarceration costs attributable to Secure Communities activation, while 6 (16%) reported minimal costs, which highlights how official oversight reports can address operational or cost questions without concluding that immigration enforcement caused longer-term imprisonment outcomes.
BJS imprisonment-rate statistics work on a different measurement track than a short detainer hold. The Bureau of Justice Statistics’ National Prisoner Statistics program produces annual national- and state-level data on prisoners in state and federal prison facilities and collects aggregate race and sex information for prisoners, and BJS defines an imprisonment rate as the number of prisoners under state or federal jurisdiction with sentences of more than one year per 100,000 U.S. residents.
In the BJS Prisoners in 2011 report, BJS reported that Hispanic males were imprisoned at 2 to 3 times the rate of white males in 2011. That statement describes a statistical relationship inside BJS’s definition of imprisonment rate and its prison-jurisdiction population, not a custody-cause attribution tied to any particular immigration enforcement program.
A useful way to compare the concepts is to separate federal detention coordination from prison statistical measurement. The same immigration-enforcement discussion can involve a short local-holding window and still be statistically distinct from prison imprisonment rates because the populations and definitions do not overlap in the same way.
Detainer and Secure Communities vs BJS imprisonment rate measurement
| Concept | What official sources describe | What official sources do not establish (in the reviewed record) |
|---|---|---|
| Immigration detainer framework | The eCFR describes a detainer as a request for notice prior to release so DHS can arrange to assume custody, with a 48-hour custody limit excluding Saturdays, Sundays, and holidays | A final explanation of who becomes imprisoned after conviction, or a causal link from detainers to imprisonment-rate changes |
| Secure Communities (as described by DHS OIG) | DHS OIG describes automated information sharing and, if necessary, requests to detain locally for up to 48 hours to allow ICE to take custody, plus reported cost perceptions | A causal study showing changes in prison imprisonment rates by race or ethnicity |
| BJS imprisonment rate | BJS defines imprisonment rate using prisoners under state or federal jurisdiction with sentences longer than one year per 100,000 U.S. residents and reports race-and-sex comparisons | Causation tied to immigration enforcement increases, since BJS’s definition and the reviewed excerpt do not attribute the cause of disparities |
This distinction matters because readers often treat detainer-related custody coordination as if it directly explains prison imprisonment rates, even though the detainer is a short coordination mechanism and BJS imprisonment rate is a longer-sentence prison population metric.
Returning to the “driven by increases in immigration enforcement” phrasing, the reviewed official sources support the existence and mechanics of federal detention coordination tools and they report race-and-sex imprisonment-rate disparities in 2011, but they do not provide a causal finding that immigration enforcement increases caused Hispanic imprisonment-rate increases. Instead, the federal regulation and form explain what detainers request of holding agencies and how long custody can last, the DHS OIG report explains operational steps and local cost perceptions, and the BJS report explains how imprisonment rate is defined and how it compares rates across groups.
