Which states or facilities hold the largest numbers of detained legal immigrants as of 2023?

1. National scale: bookings and the FY2023 headline

Official and civil-society tallies make clear that FY2023 was not a small year for immigration detention: ICE and reporting sources record approximately 273,220 people booked into ICE custody in FY2023, a figure used repeatedly in public summaries of that year’s detention activity ^{[1] [4]}. That bookings number reflects the throughput of a widely distributed system of roughly 200 facilities that includes federal contract centers, private prisons, county jails and shorter-term Border Patrol or CBP holding sites ^{[1] [5]}.

2. Where detention is concentrated: states and regional patterns

Multiple analyses describe a familiar geography: detention is concentrated in the Southwest and Southeast, where border-processing needs, long-standing contracts and bed capacity cluster detainees in large numbers ^{[2] [5]}. Freedom for Immigrants’ mapping of ICE data from mid‑2023 highlights the same pattern, indicating a small set of states held the largest populations according to ICE’s June 2023 data ^[3]. Public reporting and NGO mapping therefore point to states with large border or contract facilities — notably Texas, California, Arizona and several southeastern states — as the primary loci of detention, but the available sources do not provide a fully consistent, single ranked list for every month of 2023 ^{[3] [2] [1]}.

3. The facilities that held the most people in and around 2023

Detailed facility-level reporting from watchdogs and research groups identifies particular sites that held exceptionally large populations: Adams County Detention Center in Natchez, Mississippi is singled out as having the largest single‑facility detainee population at the end of the Biden presidency, while South Texas ICE Processing Center (Pearsall, Texas) and Stewart Detention Center (Lumpkin, Georgia) each held more than 1,500 adults in reported snapshots around that period ^[2]. Other large contract facilities such as Otay Mesa in San Diego County have historically been among the biggest in California, and national maps maintained by Freedom for Immigrants catalog more than 200 immigrant detention sites nationwide, underscoring how a few very large centers and many smaller jails together shape totals ^{[6] [3]}.

4. Why state and facility counts vary — data, definitions and hidden beds

Any attempt to rank states or facilities must confront counting differences: ICE’s published tallies generally track beds and detainees in facilities under ICE custody or contract, but state-run facilities, local jails holding migrants under intergovernmental agreements, CBP short‑term holds, and other categories can be excluded or rolled into different datasets, creating apparent discrepancies across reports ^{[7] [5]}. Advocacy groups and mapping projects fill gaps by aggregating ICE data, local records and reporting, but their methods differ, so a “largest states” list for mid‑2023 is best understood as a convergence of multiple indicators rather than a single unimpeachable ranking ^{[3] [8]}.

5. The politics behind the beds: private operators and policy choices

Analysts and watchdogs emphasize that the detention system’s geography is shaped by contracting, private prison capacity and federal policy choices that favor particular regions and large contract centers; for decades companies such as GEO Group and CoreCivic and state actors have helped determine where the largest detention footprints appear ^{[5] [3]}. Those economic and policy drivers explain why a handful of large facilities and a small set of states repeatedly surface as holding the largest numbers of detained noncitizens in 2023 even as precise month‑by‑month rankings shift depending on transfers, temporary camps and enforcement surges ^{[5] [2]}.