Texas and Mississippi have the largest backlog of immigrants in their detention centers

ICE's largest detention center is in Mississippi. With an average of 2,154 illegal immigrants, the Adams County Correctional Center was the facility with the most illegal immigrants in the entire country.

That private prison near Natchez, Miss., is followed by the South Texas ICE Processing Center in the town of Pearsall, Texas, a two-hour drive from the border.

That's according to agency data collected by the Transactional Records Access Clearinghouse (TRAC) for fiscal year 2025 through early February. In addition to the tail end of the Biden administration, this data also includes the start of the immigration offensive of the Trump administration.

Led by those two detention centers, Missississippi and Texas are the states with the largest backlogs of immigrants. The latter has eight centers among the 20 busiest, according to a review of the data by Axios. Each has more than 800 ICE detainees.

In January 2025, ICE detained 21,959 immigrants, with 11,758 apprehensions made by its own agents and 10,201 by U.S. Customs and Border Protection (CBP).

By Feb. 9, 41,169 immigrants had been booked into border agency custody. Also according to TRAC, about 45% of those had criminal records.

More than 3.7 million pending cases

Taking into account immigration cases completed in January, Montana was the state with the highest proportion of removal orders. At the other extreme was Vermont.

At the end of the month, more than 3.7 million cases were still pending before the courts. Florida is home to the county with the most residents awaiting resolution: Miami-Dade, with 158,952. It is followed by Cook County in Illinois and Los Angeles in California.

More than 188,000 individuals and families are in Alternatives to Detention (ATD) programs. The largest concentration is in San Francisco (20,000), followed closely by Chicago (19,583) and Los Angeles (16,140).

These immigrants are under a less strict surveillance regime and can remain in the communities while they continue their immigration or deportation processes. In exchange, they must wear tracking tools such as ankle monitors or register via phone calls.

Although on the latter data, TRAC warns that ICE acknowledged in the past that it had published "inaccurate" data. "TRAC has requested but not yet received underlying source documents from ICE," the organization said. That is a constant in the agency's data reviewed by the organization, with claims that there are "strange inconsistencies." In the latest update, for example, those arrested at Guantanamo Bay do not appear.