The Law of Immigration Detention: A Brief Introduction
Updated September 1, 2022
The Law of Immigration Detention: A Brief Introduction
The Immigration and Nationality Act (INA) authorizes—
event of an alien’s release, DHS may opt to enroll the alien
and in some cases requires—the Department of Homeland
in an Alternatives to Detention program, which enables the
Security (DHS) to detain non-U.S. nationals (aliens) who
agency to monitor and supervise the alien to ensure his or
are subject to removal from the United States. This
her eventual appearance at a removal proceeding.
detention scheme is multifaceted, with rules that turn on
several factors, such as whether the alien is seeking
INA § 236(a) permits an immigration officer, at any time
admission or has been lawfully admitted into the country;
during removal proceedings, to determine whether an
whether the alien has engaged in certain proscribed
arrested alien should remain in custody or be released. If
conduct; and whether the alien has been issued a final order
the alien is arrested without an administrative warrant, the
of removal. This In Focus provides a brief introduction to
custody decision generally must be made within 48 hours.
the immigration detention framework. For a more detailed
DHS regulations provide that to be released the alien must
discussion, see CRS Report R45915, Immigration
show that he or she is not a flight or security risk.
Detention: A Legal Overview, by Hillel R. Smith.
If the alien remains detained, he or she may request review
Statutory Framework
of DHS’s custody decision at a bond hearing before an
Four provisions of the INA primarily shape the immigration
immigration judge (IJ) within the Department of Justice’s
detention framework:
Executive Office for Immigration Review (EOIR). The IJ
may decide whether DHS may retain physical custody or
1. INA § 236(a) generally authorizes the detention
release the alien, and the IJ has authority to set the bond
of aliens pending a decision on whether the
amount. The IJ’s custody determination may be appealed to
alien is to be removed from the United States
the EOIR’s Board of Immigration Appeals (BIA). Federal
and permits those who are not subject to
statute generally bars judicial review of a decision whether
mandatory detention to be released on bond or
to detain or release an alien, but courts may consider habeas
their own recognizance;
corpus claims alleging that an alien’s detention is unlawful.
2. INA § 236(c) generally requires the detention of
aliens who are removable because of specified
Mandatory Detention of Criminal Aliens
criminal activity or terrorism-related grounds;
While immigration officials generally have broad discretion
to decide whether to detain aliens during the pendency of
3. INA § 235(b) generally requires the detention
removal proceedings, INA § 236(c) requires the detention
of applicants for admission who appear subject
of aliens removable on specified criminal or terrorism-
to removal, including aliens arriving at a port of
related grounds. These grounds include, for example,
entry and certain other aliens who have not been
crimes involving moral turpitude, drug crimes, aggravated
admitted or paroled into the United States; and
felonies, and membership in a terrorist organization.
4. INA § 241(a) generally requires an alien subject
to a final order of removal to be held during the
INA § 236(c) states that DHS “shall take into custody any
90-day period when the alien’s removal is
alien” who falls within one of the enumerated criminal or
effectuated, and DHS may detain an alien
terrorism-related grounds “when the alien is released” from
beyond this 90-day period if the agency is
criminal custody. The Supreme Court in Nielsen v. Preap
unable to effectuate removal and the alien falls
held that this mandatory detention scheme covers any alien
within certain categories.
who has committed a specified offense, even if not
Discretionary Detention
immediately taken into custody after release from criminal
INA § 236(a) authorizes the arrest and detention of an alien
incarceration.
pending a determination on whether the alien shall be
removed from the United States. Detention under this
Except in limited circumstances, an alien detained under
statute is discretionary, and immigration authorities need
INA § 236(c) generally may not be released on bond or his
not continue to detain an alien subject to removal unless the
or her own recognizance during removal proceedings. The
alien is subject to mandatory detention (e.g., aliens
alien may seek limited review by an IJ to determine
convicted of specified crimes under INA § 236(c)).
whether he or she falls within one of the categories of aliens
subject to mandatory detention.
If DHS arrests and detains an alien under INA §236(a), and
Mandatory Detention of Applicants for Admission
the alien is not subject to mandatory detention, the agency
Under INA § 235(b) applicants for admission must
may either (1) continue to detain the alien during the
generally be detained for removal purposes if they do not
pendency of removal proceedings, or (2) release the alien
appear clearly to be admissible. The statute defines an
on bond in the amount of at least $1,500 or on the alien’s
“applicant for admission” to include both an alien seeking
own recognizance (subject to certain conditions). In the
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The Law of Immigration Detention: A Brief Introduction
initial entry at a designated port of entry and an alien
post-order of removal, after which an alien typically must
present in the United States who has not been admitted.
be released if there is no significant likelihood of removal
in the reasonably foreseeable future. Following Zadvydas,
The detention requirements of INA § 235(b) have been
DHS established “special review procedures” to assess the
construed to apply to applicants for admission regardless of
likelihood of removal for aliens who remain detained
whether they are subject to a streamlined “expedited
beyond the 90-day removal period. In 2005, the Supreme
removal” process (e.g., those apprehended when attempting
Court in Clark v. Martinez determined, as a matter of
to enter the United States without valid entry documents) or
statutory construction, that the presumptive six-month time
are subject to formal removal proceedings (e.g., aliens
limitation read into INA § 241(a) equally applied to aliens
inadmissible because of engaging in certain criminal
who had not been lawfully admitted into the United States,
activities). This construction also applies to aliens who,
and who were being indefinitely detained after their 90-day
though initially subject to expedited removal, were found to
periods. In 2022, however, the Supreme Court in Johnson v.
have a credible fear of persecution if returned to their
Arteaga-Martinez held that § 241(a) does not require bond
country of origin, and then transferred to formal removal
hearings for aliens detained under that provision.
proceedings to pursue asylum or similar forms of relief.
Whether an alien’s prolonged detention during the
DHS may “parole” an alien otherwise subject to detention
pendency of removal proceedings raises similar
under INA § 235(b) “for urgent humanitarian reasons or
constitutional concerns remains debated. In 2003, the
significant public benefit,” enabling the alien to be released
Supreme Court in Demore v. Kim ruled that the mandatory
from the agency’s physical custody. Unlike custody
detention of certain aliens without bond (e.g., criminal
determinations under INA § 236(a), DHS’s parole decisions
aliens) during removal proceedings is “constitutionally
are not subject to administrative review.
permissible,” but the Court did not decide whether there are
any constitutional limits to the duration of this detention.
Detention of Aliens After Removal Proceedings
Some lower courts, however, have construed Demore to
INA § 241(a) governs the detention of aliens subject to a
apply only to brief periods of detention, after which an alien
final order of removal. DHS “shall detain” an alien subject
should have an opportunity to seek release on bond.
to a final order of removal during a 90-day “removal
period.” INA § 241(a) instructs that “under no circumstance
In Jennings v. Rodriguez, the Supreme Court in 2018 held
during the removal period” may DHS release an alien
that DHS has the statutory authority to detain aliens
removable on certain criminal or terrorism-related grounds.
potentially indefinitely during the pendency of removal
The alien must be released on an order of supervision if not
proceedings, but did not decide whether such prolonged
removed within the 90-day period.
detention is unconstitutional. However, some lower courts
have concluded that the detention of aliens during removal
INA § 241(a) also provides that DHS may detain an alien
proceedings without a bond hearing violates due process if
ordered removed beyond this 90-day removal period if the
the detention is unreasonably prolonged, and that the
agency is unable to effectuate removal and the alien falls
government bears the burden of proving at a bond hearing
within certain categories (e.g., criminal aliens, inadmissible
that any continued detention is justified.
aliens). DHS regulations provide that if the agency decides
to keep the alien detained, it must conduct periodic custody
In addition, a 1997 court settlement agreement known as
reviews pending efforts to secure the alien’s removal. INA
the Flores Settlement currently limits the period in which
§ 241(a) provides for no bond hearings during detention.
an alien minor may be detained by DHS. In addition, under
federal statute, an unaccompanied alien child who is subject
The Supreme Court held in Johnson v. Chavez that INA
to removal generally must be placed in the custody of the
§ 241(a) also governs the detention of aliens whose removal
Department of Health and Human Services, rather than
orders are reinstated following their unlawful reentry into
DHS, during the pendency of removal proceedings.
the United States, including those pursuing relief on
account of fear of persecution or torture in the country
Apart from judicial constraints on the length of detention,
where they would be removed.
DHS’s detention authority may be restricted in other ways.
For example, the agency has established certain standards
As discussed below, the Supreme Court has recognized
for the conditions of detention facilities, and detained aliens
constitutional constraints to post-removal order detention.
have raised due process challenges to the conditions of their
Constitutional and Other Limitations to
confinement in some cases. Some courts also have held that
DHS’s Detention Authority
the Fourth Amendment limits when immigration
“detainers” may be used by DHS to take custody of aliens
DHS has broad statutory authority to detain aliens identified
from state and local law enforcement authorities.
for removal, but the scope of that authority may be subject
to constitutional constraints, particularly if detention
Thus, although DHS generally has broad detention
becomes prolonged.
authority, that authority is not unfettered, and due process
and other constitutional considerations may inform the
In 2001, the Supreme Court in Zadvydas v. Davis
duration and conditions of the alien’s detention.
concluded that the indefinite detention of a lawfully
admitted alien ordered removed would raise “serious
Hillel R. Smith, Legislative Attorney
constitutional concerns.” The Court construed INA § 241(a)
as having an implicit, temporal limitation of six months
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The Law of Immigration Detention: A Brief Introduction
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