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Introduction
Over the past nine months since the beginning of the second Trump administration, Immigration and Customs Enforcement (ICE) spending on detention has spiked, coinciding with a dramatic shift in policies that prioritize detention over targeted enforcement. A modern record of more than 66,000 individuals were being held ICE detention in November 2025, and the administration continues to re-open, expand, and construct new detention facilities to support its stated goal of “mass deportations.” ICE has partnered with state governments to expand capacity, sometimes housing detainees in substandard conditions.
Moreover, the individuals in these detention facilities are a very different population than was previously being held by ICE. The unprecedented scale of spending on ICE detention and the increased number of immigrants subject to mandatory detention results in high taxpayer spending to detain non-criminals.[1] This paper examines the dramatic escalation in detention spending, analyzes how recent policy changes have expanded mandatory detention to include long-term residents with no criminal history, and evaluates the implications of these shifts.
The Cost of Immigration Detention
The growth of immigration detention in the U.S. in recent decades has been highly costly to American taxpayers. Recent developments have only increased detention spending, which had remained nearly at or above three billion dollars from FY 2019 through FY 2024. The One Big Beautiful Bill Act (OBBBA), enacted in July 2025, includes $45 billion for expanding detention capacity over the next four years. The reconciliation package ensures an additional $11.25 billion for ICE detention per year. This exceeds the Department of Justice’s budget request of $8.25 billion for FY2026 for the entire federal prison system, which holds more than 155,000 inmates. As a result of the OBBBA, ICE’s total detention budget for FY2025 surpassed $14 billion, more than 400% greater than the funding for detention in FY2024 and nearly 800% greater than FY2010 immigration detention funding.
[2] *For FY2025, revised enacted funding levels (the amount of money appropriated by Congress plus any supplemental or reprogrammed funding) are not yet available. ** For FY2026, funding levels shown are the president’s budget request for ICE Custody Operations.
At the time of writing, the FY2026 appropriations process is ongoing. The administration and congressional Republicans, who control both chambers of Congress, have continued to make immigration detention and enforcement a top priority. The level of funding ultimately approved is likely to largely follow the president’s budget request. The Trump administration is now pursuing an aggressive immigration enforcement strategy that has resulted in historic numbers of individuals being held in ICE detention. During its first term from FY2019 to FY2021, the Trump administration had less than four billion dollars to spend on ICE detention per year. In FY2025, the first year of the second Trump administration, more than $14 billion was appropriated for ICE detention, with potentially even greater funding in future fiscal years.
Mandatory Detention and Non-Criminals in ICE Detention
The number of individuals in ICE detention was reduced substantially during the COVID-19 pandemic and began increasing in FY2023 amid heightened irregular border crossings. Detention has historically been reserved for recent border crossers and individuals who pose public safety threats. The unprecedented funding in OBBBA has enabled the administration to detain an increasing number (and proportion) of non-criminal immigrants. Prior to January 2025, the average daily population detained by ICE was largely composed of individuals with criminal convictions. Since January 2025, however, the number of individuals with pending criminal charges or no criminal charges in ICE detention have surged dramatically.
As the Trump administration has pursued large-scale detention and deportation policies in 2025, the makeup of immigrants of ICE detention has shifted substantially. In September 2025, the average daily population in ICE detention included 16,251 individuals with no criminal record, 15,719 with a prior criminal conviction, and 14,332 with pending criminal charges. This is a sharp reversal from enforcement patterns during previous administrations, when the majority of those in ICE detention had criminal convictions.
The number of non-criminal immigrants in ICE detention has surged following a fundamental policy shift implemented through agency directives. A July 8, 2025, memo from ICE Acting Director Todd Lyons controversially reinterpreted decades-old immigration statutes to impose mandatory detention on all “arriving aliens.” Multiple federal judges have ruled against the policy. Immigration attorneys argue the administration is reinterpreting immigration laws to expand mandatory detention beyond its original scope to meet mass deportation goals.
On September 5, 2025, the Board of Immigration Appeals (BIA) issued a ruling that anyone in deportation proceedings who entered the U.S. without inspection cannot be released on bond. Previously, individuals in this circumstance who had lived in the U.S. for more than two years could be released on bond at the discretion of an immigration judge. Advocates argue the BIA’s interpretation effectively applies mandatory detention to all individuals who entered the United States without inspection, regardless of when they arrived, their ties to the community, or criminal history.
This policy change represents a dramatic expansion of mandatory detention that shifts immigration detention away from a focus on public safety threats toward the mass incarceration of non-criminal immigrants. The elimination of bond hearings means that detained individuals will remain in custody for the duration of their removal proceedings, which can take months or years depending on court backlogs. There were 39,000 detainees in ICE custody when President Trump returned to the White House in January 2025. That number rose to a record 66,000 in November and could reach as high as 107,000 by January 2026. As of September 2025, individuals spent an average of 44 days in immigration detention, at an average cost of $152 per day, although the cost varies widely across facilities. With millions of long-term U.S. residents now subject to the same mandatory detention provisions as recent border crossers, the non-criminal ICE detention population is expected to continue expanding, driving detention costs to unprecedented levels (exceeding $14 billion per year with funding from the OBBA) while limiting ICE’s ability to prioritize resources toward individuals who pose genuine public safety concerns.
Conclusion
The expansion of ICE detention spending under the second Trump administration represents the largest investment in immigration detention in U.S. history. Detention funding has increased more than 400% from approximately $3 billion in FY2019 to over $14 billion in FY2025, with projections exceeding $15 billion in FY2026. The OBBBA commits taxpayers to $11.25 billion annually in additional detention spending through FY2029, locking in this unprecedented funding level for years regardless of changing enforcement needs, in the absence of action by a future Congress.
This surge in spending has fundamentally transformed who is being detained and why. For the first time, non-criminal immigrants now outnumber those with criminal convictions in ICE custody. Policy changes eliminating bond hearings for millions of long-term U.S. residents who entered without inspection have expanded mandatory detention far beyond recent border crossers, ensuring this shift will accelerate. The reconciliation funding enables ICE to pursue plans for over 100,000 detention beds by early 2026, approaching the capacity of the entire federal prison system to incarcerate a population that is predominantly non-criminal.
As detention capacity expands and the non-criminal population grows, it will become increasingly questionable whether detaining tens of thousands of individuals with no criminal record at a cost exceeding $14 billion annually represents an effective or fiscally responsible use of federal resources. The OBBBA commits taxpayers to this enforcement approach through September 30, 2029, creating detention infrastructure that will persist beyond any single administration. Policymakers and the public will be evaluating the necessity of this – the largest immigration detention expansion in American history – in the coming years.
[1] While violations of immigration law such as unlawful presence or overstaying a visa are civil offenses with immigration consequences, they are not criminal offenses. Some immigration violations like illegal entry (a misdemeanor) and illegal reentry after removal (a felony) are criminal offenses, but individuals convicted of these immigration-specific crimes are rarely public safety threats. Law Enforcement Immigration Task Force “Fact Sheet: Immigrants and Crime” https://leitf.org/2018/06/fact-sheet-immigrants-crime/.
[2] U.S. Immigration and Customs Enforcement, “Congressional Budget Justification FY 2021,” 10, https://www.dhs.gov/sites/default/files/publications/u.s._immigration_and_customs_enforcement_0.pdf; Congressional Budget Justification FY 2023,” 5, https://www.dhs.gov/sites/default/files/2022-03/U.S.%20Immigration%20and%20Customs%20Enforcement_Remediated.pdf; “Congressional Budget Justification FY 2026,” 5, https://www.dhs.gov/sites/default/files/2025-06/25_0613_ice_fy26-congressional-budget-justificatin.pdf; National Immigration Forum, “One Big Beautiful Bill Act: Immigration Provisions,” https://immigrationforum.org/article/one-big-beautiful-bill-act-immigration-provisions/.
[3] U.S. Immigration and Customs Enforcement. “Detention Statistics.” Accessed October 2, 2025. https://www.ice.gov/detain/detention-management.