How do DHS 'encounters' differ from counts of unique migrants and how are they recorded?
Executive summary
DHS "encounters" count events — every time a removable alien is stopped, apprehended, inadmissible at a port of entry, or expelled — not distinct people, so one person can generate multiple encounters in a reporting period [1] [2]. The agency records these events across CBP components (USBP and OFO), includes Title 42 expulsions in that total, and uses internal record‑linking and unique identifiers to approximate—but not perfectly recover—the number of unique individuals [3] [2] [4].
1. What DHS means by an “encounter” and what it includes
DHS and CBP define an "encounter" as a recorded event in which a removable alien is encountered by U.S. Border Patrol between ports of entry, or an applicant for admission is deemed inadmissible at a port of entry by Office of Field Operations — and monthly encounter totals explicitly incorporate Title 42 expulsions as a type of encounter [1] [3]. The encounter unit of measure therefore aggregates different operational outcomes—Title 8 apprehensions, OFO inadmissibles, and Title 42 expulsions—so the headline "encounters" line mixes people who were processed into removal proceedings, people expelled quickly on public health grounds, and those stopped at ports seeking admission [3] [5].
2. Why encounters are not the same as counts of unique migrants
DHS encounter tables count events and "count people encountered more than once during a reporting period multiple times in the tables," meaning repeat crossings, re‑entries after expulsion, or multiple interactions with different components inflate encounter totals relative to unique individuals [1] [2]. CBP itself has noted in reporting that a substantial share of encounters are repeat encounters — for example, in some months over 20% of encounters had at least one prior encounter in the past 12 months — and analyses show the fraction of unique encounters can be far lower than the raw encounter total implies [6] [7].
3. How DHS attempts to record and deduplicate encounters
To move from event totals toward person‑level counts, DHS’ Office of Immigration Statistics and related offices use unique record identifiers, linkages across agency systems, and standardization processes to deduplicate and match encounters to enforcement outcomes; the Enforcement Lifecycle work links many DHS and DOJ systems to create a more complete view of unique encounters and subsequent actions [2] [4]. Despite these methods, components warn that records may not match other agency reports because of differing methodologies and "as‑of" dates, and that deduplication efforts depend on available identifiers and system linkages that have improved only recently [2] [8].
4. Operational changes that affect encounter counts (Title 42 and policy shifts)
The creation of the encounter category itself and the composition of encounter totals were shaped by policy changes: CBP shifted terminology and reporting after Title 42 practices began in 2020, combining apprehensions and expulsions into encounter counts; when Title 42 was in effect, many people were expelled quickly and sometimes tried again, producing additional encounters for the same individual [5] [6]. DHS statements and external analyses also show that expulsions, repatriations, and the availability of lawful pathways can change the relationship between encounters and unique people, since policy affects whether an encounter becomes a short expulsion, a detention, or a full case in immigration court [9] [10].
5. What the encounter metric can and cannot reliably tell policymakers and the public
Encounters reliably measure operational workload and the number of recorded events that CBP and OFO must process, making them useful for resource planning and short‑term trend signals [11] [9]. Encounters do not, however, equal the number of distinct migrants who successfully entered the U.S.; estimating unique individuals or successful entries requires additional modeling (apprehension rates, surveys) and lifecycle linkage across systems — work DHS and independent groups have undertaken but which still leaves uncertainty about exact unique counts [12] [4]. Political actors sometimes conflate encounters with unique new migrants to make claims about totals; independent reporting and DHS documentation both warn against that leap because repeat encounters and expulsions meaningfully distort the raw event counts [6] [7].
6. Bottom line and reporting limits
The bottom line is straightforward: "encounters" are event counts that mix apprehensions, inadmissibles, and expulsions and intentionally count repeated interactions multiple times; DHS uses identifiers and lifecycle linkages to estimate unique individuals but cannot fully eliminate duplication or reconcile all reporting differences in real time [1] [4]. This explanation reflects DHS and CBP documentation and multiple analyses, and where source data lack person‑level certainty, reporting rightly qualifies the limits of what encounter totals alone can prove [2] [8].