ICE Detention Numbers Drop Significantly in Past Two Months, But There's More to the Story...
The latest Immigration and Customs Enforcement (ICE) detention data shows a significant decline of nearly 10,000 people over the past two months to a current total detained population of 60,311 people as of April 4.1 ICE did not publish data during DHS budget negotiations that resulted in what was referred to as a shutdown. This latest Thursday-evening data release puts the agency back on track with its biweekly schedule. The latest data shows a drop in detention, a drop in ICE arrests, a change in the composition of who is in detention, and a spike in people on GPS ankle monitors.
Let’s go over the latest facts, but before we do, permit me a quick plug to ask that if you aren’t one of the generous readers who supports this work with a paid subscription, please learn about your options for doing so at austinkocher.substack.com/subscribe. There is a lot happening on my Substack these days, so I could really use some help getting the word out to people outside the immigration bubble, so it would be amazing if you could vouch for this work online/offline with your networks. Thank you.
As I said, detention numbers have declined considerably to about the levels at the end of FY 2025 in September 2025—so the lowest in six months. To put it this way might suggest to critics of the administration that things are “getting better” or to the MAGA movement that the administration isn’t doing enough. Remember that, even with the decline, these numbers are at historical levels and that it’s not unusual for detention numbers to fluctuate. Still, this is quite a decline. The DHS shutdown could have played a major role here, but others are more qualified than me to trace that connection. Instead, the data itself gives us some clues and reinforces a larger point that I’ve made repeatedly (including for years before this administration). Let me explain…
As I’ve written before, almost as a rule, the growth of immigrant detention is driven more than anything else by immigrants with no criminal history. I predicted this at the start of the Trump administration and that prediction has come true.
“I fully expect that the number of immigrants with no criminal histories will continue to increase and overtake the total number of immigrants with criminal convictions or charges as ICE's detention capacity expands. Despite what the administration says, the truth is that total population of immigrants with criminal convictions that end up in detention is far less elastic than the population of immigrants with no criminal histories.”
The fundamental lesson here is that major fluctuations in arrests, detentions, and deportations—at the national, aggregate level—driven almost entirely by immigrants with no criminal history. It’s the result of basic sociological factors surrounding rates of participation in crimes and the nature of immigration enforcement itself. There’s no great mystery to it. But the principle holds true both ways. Growth in detention is driven by “other immigration violators” (i.e., immigrants with no criminal history in the U.S. who are suspected of an immigration violation); but so are sharp declines.2 To put it the other way around, the total number of immigrants arrested, detained and deported with criminal charges and convictions are, on the whole, incredibly sticky. At a certain point, it doesn’t budge that much. Thus, the decline in detention numbers comes from some combination of fewer immigrants without criminal histories are being arrested and possibly more are being released. Meanwhile, the other two groups have barely budged.
I will add this tidbit for those reading past the headline: for the first time I can recall, for as long as I’ve been looking at detention data, the total number of people with criminal convictions is now the smallest of the three groups. It’s not by much, but if you’re looking for another data point that contradicts the administration’s wild claims about “the worst of the worst”, there you have it. Remember that these are ICE arrests only; I do not include CBP arrests in this data.
What about ICE arrest? We have seen a decline in the average number of daily ICE arrests since it peaked in January during Operation Midway Blitz. The full month of March and the first four days of April show lower daily arrests than any month going back to August 2025. Again, that’s still high, but it contradicts the idea that immigration enforcement can simply grow exponentially forever simply out of the Pure Will (der Wille) of Stephen Miller. As I wrote recently, the Trump administration is facing setbacks, bottlenecks, lawsuits, logistical challenges, and so forth that provides a gut check (possibly temporary) about whether the administration will be able to meet its sensational goal of a million deportations a year.
The total detained population—ICE and CBP arrests together—has shifted from being about half “OIV” to about 40%. I don’t have much more to say about this that I haven’t said above, just another way to look at the data.
One place where we have seen lots of growth is the number of immigrants now monitored on GPS ankle monitors. The overall number of people on alternatives to detention (ATD) (aka, electronic monitoring; aka ISAP) is at 180,701. The trend in ICE’s Alternatives to Detention enrollment continues, with ICE shuffling people off the smartphone tracking app known as SmartLINK and ramping up the number of people on the more punitive GPS ankle monitors. There are now 46,302 people on GPS ankle monitors, continuing the upward trajectory that has marked this technology’s expansion under the current administration.
Please Use and Share These Visualizations
Please feel free to use these visualizations any way that you see fit with attribution, no need to ask permission. Note that you can download the data for each visualization, download a static image, or embed the visualization in your own website. Spread the data. Thanks for reading.
What Should We Call “Detention Centers”?
Listen to my conversation with John Washington from earlier this week.
Events Tomorrow
Register to learn more about the Dignity Act and join me at GWU if you are in the DC area.
The cover image this week is from the book Undocumented: The Architecture of Migrant Detention by Tings Chak. I talk about this book and many other creative works of immigration research in my previous post below.
I sometimes forget to say this, but please remember that this is total number of people in detention at the time of the data extraction. The total number of people who go THROUGH the system is much higher than this, and, technically speaking, smaller daily detention numbers can still impact the same or more people IF people are being pushed through the system faster.
Just to reinforce this idea that it’s not new, I wrote about this for TRAC during the previous Trump administration (https://tracreports.org/immigration/reports/583/) and at the start of the pandemic (https://tracreports.org/immigration/reports/601/).