How many migrants were apprehended at the U.S.–Mexico border in 2021 versus 2024 and what do those numbers say about enforcement?

1. The basic numbers available in the record: 2024’s documented total and the reporting gap for 2021

U.S. Customs and Border Protection reports and watchdog summaries in the dataset show 2024 Border Patrol apprehensions between ports of entry totaled about 1,530,523 encounters for the fiscal year, a headline figure used by researchers and advocacy groups to describe 2024 migration flows ^{[1] [6]}. The collection of sources provided does not include a single, explicit Border Patrol “apprehensions in fiscal 2021” line to cite directly; contemporary reporting instead describes 2021 as a rebound year where encounters rose sharply compared with 2020 but stops short of an authoritative number in these excerpts, so a direct numeric-to-numeric claim from this packet would exceed what the supplied sources document ^{[7] [8]}.

2. Why 2024’s lower totals don’t automatically mean “stronger enforcement” alone

Analysts and NGOs attribute the pronounced drop in 2024 encounters to a constellation of measures: an executive rule from the U.S. administration that made asylum access harder during busy periods, expanded use of CBP One appointments at ports of entry, and much greater enforcement on the Mexican side of the border—each of which reduced the number of people reaching the U.S. border or being processed there ^{[3] [5] [4]}. Migration-policy scholars caution that declines driven by policy or diplomatic cooperation reflect deterrence and management changes rather than a single, uniformly stronger U.S. enforcement posture; Mexico’s actions, in particular, accounted for large parts of the drop in arrivals ^[4].

3. What the composition of encounters in 2024 reveals about enforcement choices

The 2024 numbers show a shift in where and how migrants are counted: CBP encounter tallies in 2024 included large numbers at ports of entry via CBP One appointments as well as Border Patrol apprehensions between ports of entry, and families and children remained a substantial share of encounters—about 43 percent of the nationwide total and a similar share among Border Patrol apprehensions—highlighting that policy changes affected groups differently ^{[9] [1]}. In other words, reduced apprehensions do not necessarily mean fewer people sought to come; they often reflect redirection, expulsions, or changes to whether someone is processed as an “apprehension,” an “inadmissible” or an expulsion ^[6].

4. Enforcement as a mix of deterrence, bilateral pressure, and legal tools

The available reporting frames enforcement in 2024 as multi-layered: U.S. rule changes made asylum harder during surges, CBP operational changes encouraged use of official ports, and Mexico intervened to slow northbound flows—together producing large year-on-year declines in Border Patrol apprehensions ^{[3] [5] [4]}. That combination complicates claims that a single agency “apprehended fewer migrants because it became more effective”; instead, the decline is evidence of coordinated deterrence strategies and shifting migration routes and processing regimes ^[5].

5. What can and cannot be concluded from the comparison given the sources

From the supplied reporting it is sound to conclude that 2024 recorded roughly 1.53 million Border Patrol apprehensions and that encounters fell markedly from the record highs of 2023 into 2024 due to policy and enforcement actions on both sides of the border ^{[1] [3]}. It is not possible, based solely on these excerpts, to produce a single, sourced FY2021 “aprehensions at the U.S.–Mexico border” number for a strict apples-to-apples comparison without consulting the underlying CBP monthly/fiscal reports or Congressional Research Service tables not included here; therefore, any direct numeric contrast should be treated as incomplete absent those primary CBP or CRS figures ^{[2] [7]}.