Immigrant Detention by the Numbers: A Baseline for Evaluating ICE's Ramped-Up Enforcement Efforts
ICE's latest detention data is the last look at numbers from the Biden administration and a baseline for the Trump administration. Plus: listen to my podcast interview with attorney Mo Goldman.
ICE released new immigration detention data today. Since this is the final release of data that reflects the Biden administration, it represents a baseline for us to objectively evaluate the impact of Trump’s immigration enforcement policies. Let’s talk about it.
Trump’s executive orders on immigration have received a lot of attention so far, and rightly so. However, as I told The Guardian the other day, Immigration and Customs Enforcement (ICE), the main enforcement agency away from the border is not going to wait for the policy analysts to make sense of the EOs to begin to act.
And act is exactly what they’ve done. Already there are verified reports of ICE sweeps and raids in Newark, New Jersey, and a few other locations, as well as a flurry of unverified reports of ICE activity across the country driven, in no small part, by fear and misunderstanding about the routine nature of immigration enforcement.
The White House and ICE are contributing to the fear in simple ways by attributing even routine enforcement to the fact that Trump is now in office. For example, the White House tweeted a photo of ICE officers marching a line of young presumably Latino males onto a military cargo plane with the caption “Deportation Flights Have Begun.” The entire photograph is staged for maximum political effect.
Thomas Cartwright, who tracks deportation flights carefully responded to the tweet with the following reality check:
“Theater of the absurd. The only thing new about this is subjecting people to transport on a cargo plane rather than charter and the LOWER number of people on the plane – 75-80 compared to the average for ICE deportation flights to Guatemala of 125. In 2024 there were 508 deportation flights to Guatemala and in 2020 – 2023: 247, 184, 369, and 470, respectively. The 508 in 2024 represents just under an average of 10 deportation flights per week to Guatemala. Counting this flight there have been only 5 this week through Thursday.”
Similarly, ICE has begun to report data related to enforcement activity. They also posted today that they made 538 arrests and lodged 373 detainers. (For reference: a detainer is a request that ICE sends to a local law enforcement agency, like a sheriff’s office, to ask them to hold an immigrant also ICE can come take custody from jail, or to ask them to inform ICE when the person will be released from jail so that ICE can arrest them after they leave.)
As many people pointed out, these numbers are actually entirely within the norm of the Biden administration. These numbers are actually quite normal. Aaron Reichlin-Melnick from the American Immigration Council pointed out that: “FY2024, under Biden, average daily ICE arrests was 310 and average daily ICE detainers served was 409.”
None of this is to say that ICE isn’t doing enforcement: they clearly are. But as I have been saying for months now, it’s crucial that we understand the difference between the spectacle of enforcement that feeds into Trump’s unique brand of presidential politics and the reality of where, how, and why ICE’s enforcement practices actually change.
One way of remaining clear-headed during these tumultuous times is by looking at immigration enforcement data and putting it in its proper context. Every few weeks, ICE releases data specifically on immigrants who are held in custody as well as immigrants that it monitors through the agency’s “alternatives to detention” program. I am going to have a lot more to say about both of these programs in the coming weeks—and especially the role that the Biden administration played in creating a functioning deportation to hand off to Trump.
I have been using this data as part of my research for years now and, as long as ICE continues to produce it (as they are required by Congress to do), I will keep you up-to-date with the facts.
Just a quick housekeeping note here. A lot of you are reading these posts for the first time, so I expect that my readers bring a wide range of comfort levels with charts and graphs, and with the details of immigration data. If this is your first look at immigration enforcement data and you have a question, please pop it into the comments so we make sure not to lose anyone along the way. I want this to be interesting and informative, not overwhelming or alienating.
Okay, let’s look at the data.
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Detention Data
According to the latest data, there are 39,703 immigrants held in ICE’s detention facilities across the country as of 1/12/2025. This number is a crucial baseline because it represents the last number we’ll see that reflects the results of the Biden administration’s enforcement policies. This number will be one of the most important high-level indicators of the impact of the Trump administration’s immigration policies.
Now let’s have a closer look at how this number has changed over time since the start of the Biden administration going back to January 2021.
Notice that I separated out detentions that came through ICE and those that came through CBP. ICE operates across the country, including at the border, but they are most associated with “interior enforcement”, or enforcement that happens away from the border. Customs and Border Protection (CBP) operates more strictly at the border (although not entirely as my colleague Reece Jones has demonstrated). Therefore, understanding the absolute and relative number of people in detention that came through each agency gives us a general idea of where enforcement activity is happening.
As you can see, when Biden took office during the pandemic, detention numbers were down considerably from their height during the Trump administration (not shown here) which reached over 60,000. Numbers have increased over time, with ICE’s numbers seeing a very steady increase and CBP’s numbers seeing much more fluctuation. This is because CBP is, in a way, dependent upon who comes across the border whereas ICE’s numbers are really as result of how much they are prioritizing interior enforcement.
Let’s look at another data point: the breakdown of people in detention based on criminal history. Some people will not like that I even bring this up, but this is going to be an important indicator over the next four years so we may as well break the ice. (Accidental pun.) As we can see, most people in detention only have immigration violations on their record, while a smaller number of detained people have charges or convictions for various criminal offenses. I can say from having looked at detailed data many times, most of the convictions here are not very serious (as far as criminal charges go), and some are.
Now let me make a prediction that you can hold me to. As detention numbers increase, the percentage of people in detention in the category “Other Immigration Violator” is going to steadily increase, as well. This is one of the contradictions of Trump’s conflation of dangerous criminality and immigrants. We know this through years of observation and data analysis: there simply are not enough immigrants in the country with criminal convictions to enable the Trump administration to massively grow detention and deportation alone. They will have to go after a growing number of immigrants with no criminal histories. This is not a distinction the Trump administration particularly cares about, mind you; they’ve said everyone is a priority. But I’m pointing it out because I promise you—like, I’m literally promising you—that six months from now, the major newspapers and broadcast news outlets will be reporting about this observation and asking the administration about the contrast between their “tough on crime” rhetoric and the actual breakdown of the data.
Like I said, I fully expect detention numbers to increase. Why?
First, any actual increase in ICE’s enforcement activities are likely to result in an increase in the number of immigrants booked into detention centers. That’s fairly common sense, although I want to emphasize that, simply as a practical matter, most encounters with ICE do not result in long-term detention because the agency simply doesn’t have (and never has had, and probably never will have) the capacity to hold every single person in detention indefinitely. Nevertheless, Trump and his immigration officials have been very clear that they want to increase detention.
Second, an important piece of legislation known as the Laken Riley Act has garnered bipartisan support and is likely to become law. The bill purportedly emerged from the tragic and brutal killing of Laken Riley, a nursing student in Georgia, by an immigrant early last year. The LRA will give standing to the states to sue the federal government over immigration enforcement practices and it will expand the use of what is called “mandatory detention.” In a nutshell, it’s usually up to ICE to decide who they want to keep in detention and who they want to release due to humanitarian reasons or because of limits of detention capacity. However, the law says that in certain cases, ICE must hold a person in detention and is not allowed to release them. Those are “mandatory detention” cases, and the LRA will expand these cases.
Alternatives to Detention
In addition to detention, ICE also monitors an additional 188,304 immigrants through their “alternative to detention” (ATD) program. ATD is a way that ICE keeps close tabs on people who are in the country who have pending cases before the immigration courts or who already have a deportation order.
As you can see, the number of people ICE can monitor on ATD vastly overshadows the number of people they can detain at any point in time. ICE uses several different types of technologies to do this, including GPS ankle monitors (what people probably most associate with electronic monitoring), as well as a smartphone app called SmartLINK and other forms of telephonic monitoring.
Like the detained population, we can see that there has been a slight increase in the number of people monitored on ATD. I do not know what will happen with this program.
On the one hand, I have been critical of the agency for spending money on technology-based monitoring rather than simply providing people with attorneys, which seems to be the main determining factor over whether people go to their court hearings and comply with parole. On the other hand, Republicans have been critical of Biden’s use of ATD because they view it (entirely wrongly, in my view) as some sort of easy way out of detention.
ATD doesn’t conform to the splashy spectacles that Trump wants to see. On the other hand, there is absolutely positively no way that ICE can terminate ATD tomorrow and put 200,000 people into detention centers. They do not have the capacity and even if they build toward it, I don’t see how they would even get there over the next four years. That’s why the future of the ATD numbers is more of an unknown.
Want to Learn More about Detention and ATD?
One advantage to having published about 220 substantive posts on Substack is that you now have access to a large library of resources. If you want to learn more about ICE’s electronic monitoring program, commonly (but misleadingly) referred to as “Alternatives to Detention”, I have a whole section of this newsletter devoted just to ATD. Here are two essential posts to get you started:
And if you want to learn more about the backstory of ICE’s immigrant detention system, I also have a whole section of this newsletter devoted to detention.
Listen to “Immigration Ain’t Easy” with Mo Goldman
I first met Mo during a two-month-long intensive period of fieldwork along the US-Mexico border. Mo is an immigration attorney in Arizona who also runs a fun and informative podcast called Immigration Ain’t Easy. He invited me onto his show recently and the episode just came out today. Huge thanks to Mo for the conversation. You’ll love listening to it if you like getting the backstory about how the immigration research sausage is made, why I got into this field in the first place, and much more. I’ll add the episode description below so you get a preview.
“Anyone who wants the facts on immigration controls, policing and border enforcement must follow/subscribe to Dr. Austin Kocher on social media and through his writings on Substack. He is a must follow! His research and data has been widely cited to and noted in both academic and media publications. Dr. Kocher is a geographer and Assistant Research Professor in the Office of Research and Creative Activity in the S.I. Newhouse of Public Communication at Syracuse University (GO ORANGE!!!). He was previously at the Civic Research Data Lab (CRDL) and the Transactional Records Access Clearinghouse (TRAC), a research lab at Syracuse University that uses Freedom of Information Act (FOIA) requests to study the U.S. immigration enforcement apparatus. In this interview we discuss Dr. Kocher's unconventional path to becoming a well-known expert on immigration enforcement.”
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So if ICE has 39,703 detained for 41,000 beds AND they detained around 2,700 people over Sunday-Monday, they're out of beds, no?