Overall, the number detained is down slightly from a height during the Biden administration of 39,748 on November 5. But the latest numbers still represent around two and a half times the detention levels at the end of the Trump administration. Since January 2021, changes in detention numbers have been largely driven by increases in CBP border arrests. Back then, noncitizens detained from ICE arrests were around 10,000 – little changed from today.

Another factor that influences detention numbers is the length of stay in detention. If fewer people are booked into detention but people remain locked up for longer periods of time, higher detention numbers can result. In fact, ICE reports that the overall length of detention stays have gone up so far this fiscal year, from an average of 44.2 days in October, to 47.9 days in November to now 51.8 days so far in December. Notably, in October, detainees arrested by ICE and CBP remained in detention for roughly the same number of days. However, average length of stays for those arrested along the border by CBP have increased to 56.4 days on average compared to a slight decline now among detainees arrested by ICE to 41.6 days.

Highlights from data updated in TRAC's Detention Quick Facts tool show that:

• Immigration and Customs Enforcement held 36,263 in ICE detention according to data current as of December 17, 2023.

• 24,212 out of 36,263—or 66.8%—held in ICE detention have no criminal record, according to data current as of December 17, 2023. Many more have only minor offenses, including traffic violations.

• ICE relied on detention facilities in Texas to house the most people during FY 2024, according to data current as of December 11, 2023.

• ICE arrested 6,755 and CBP arrested 10,913 of the 17,668 people booked into detention by ICE during November 2023.

• South Texas Family Residential Center in Dilley, Texas held the largest number of ICE detainees so far in FY 2024, averaging 1,963 per day (as of December 2023).

• ICE Alternatives to Detention (ATD) programs are currently monitoring 192,163 families and single individuals, according to data current as of December 16, 2023.

• San Francisco's area office has highest number in ICE's Alternatives to Detention (ATD) monitoring programs, according to data current as of December 16, 2023.

For more information, see TRAC's Quick Facts tools or click here to learn more about TRAC's entire suite of immigration tools.