Last week, the Department of Homeland Security issued a year-end announcement meant to close the book on immigration in 2025. According to DHS, more than 2.5 million illegal aliens have left the United States since January, including roughly 600,000 formal deportations and about 1.9 million voluntary departures, driven by the return of enforcement consequences. The department described the figure as historic, evidence that control has been restored after years of drift. And until the United States builds the capacity to see it clearly, risk at this scale will remain the country’s most dangerous unknown. The timing matters. This announcement followed the most permissive period of illegal migration in modern U.S. history. Between January 2021 and December 2024, the full span of the Biden administration, approximately 11 million illegal border encounters were recorded, according to Customs and Border Protection data compiled and visualized by NBC News. That surge did more than strain capacity. It altered the demographic and security profile of illegal migration into the United States. Deportation totals tell us how many have left. They tell us far less about who entered, from where, and what risk remains inside the country as a result of the surge that preceded them. The defining feature of the Biden-era intake was not volume alone. It was origin. For decades, illegal migration into the United States was largely regional. That model collapsed during the Biden years. Migrants arrived from more than 160 countries, and by fiscal year 2023, more than half of all illegal encounters involved migrants from outside Mexico and Central America, a structural shift documented by CBP and widely reported. This was not a temporary spike. It was a reorientation of the border itself, with implications deportation tallies cannot resolve. The origin data is where the concern sharpens. During the surge years, encounters from Special Interest Alien countries, nations flagged by U.S. authorities for terrorism, intelligence, or security concerns, rose markedly. CBP nationality data cited in congressional correspondence through October 2023, combined with elevated flows through fiscal year 2024, shows tens of thousands of illegal entrants from adversarial regimes, failed states, Islamist conflict zones, Africa, Eurasia, and Central Asia across the Biden era. Turkey alone accounted for more than 30,800 encounters by October 2023, and continued crossings through 2024 place conservative full-era estimates well above 40,000. Turkey occupies a complex position in the security landscape: a NATO member that has also served as a transit hub for smugglers and foreign fighters moving through Syria and Iraq. Vetting at this scale, from this environment, cannot be resolved in a brief border screening. From Central Asia, the figures were also striking. Uzbekistan recorded 13,624 encounters by late 2023, with continued migration through 2024 placing full-era figures in the high-teens to low-20,000s. Afghan nationals, arriving largely after the Taliban takeover, likely totaled between 8,000 and 10,000 across the Biden years, while Pakistani nationals exceeded 2,200 and likely approached 2,500 across the full term. From the Middle East, the numbers were smaller but significant in context. Iranian nationals, from a designated state sponsor of terrorism with no meaningful intelligence cooperation with the United States, were encountered in the high hundreds to roughly 1,000 across the four-year period. Syrian nationals, arriving from a collapsed state fragmented by ISIS remnants, al-Qaeda affiliates, and Iranian-backed militias, reached the high hundreds to low thousands once fiscal year 2024 is included. Iraqi nationals, originating from a militia-dominated post-war environment with incomplete civil records, similarly reached several hundred to over a thousand encounters across the term. Across North Africa and the Arab world, the pattern persisted. Egyptian nationals exceeded 4,000 encounters during the Biden era. Libya, fractured by warlords, arms trafficking, and jihadist corridors, contributed several hundred encounters, each largely unverifiable beyond self-reported data. From the Arabian Peninsula, Yemeni nationals, originating from a war-torn country dominated by armed factions aligned with designated terrorist groups, reached several hundred encounters across the administration. From Sub-Saharan Africa, the figures grew more pronounced. Somalia, synonymous with state failure and extremist infiltration, accounted for thousands of encounters across the Biden era, arriving from a country where civil records are unreliable and diaspora networks have been exploited by jihadist groups for decades. Mauritania alone exceeded 15,000 encounters by late 2023, with continued flow through 2024, one of the most significant Sahelian migration surges on record. The surge also extended deep into Eurasia and South Asia, further underscoring how globalized and difficult to vet the intake became. Russia accounted for approximately 3,000 to 4,000 encounters across the Biden years, with numbers rising after the 2022 invasion of Ukraine. Even North Korea, one of the world’s most closed regimes, registered roughly 40 to 70 encounters, insignificant in volume but notable given the absence of documentation and intelligence cooperation. From South Asia, the numbers were larger. India emerged as one of the single largest non-Western Hemisphere source countries, with between 65,000 and 75,000 encounters across fiscal years 2021 to 2024. Bangladesh accounted for approximately 7,000 to 9,000 encounters, Nepal for roughly 6,000 to 8,000, and Sri Lanka for about 1,000 to 2,000 across the four years. Layered on top of all of this was the most under-examined alarm bell of the period: China. In fiscal year 2023 alone, U.S. border authorities encountered roughly 33,000 to 37,000 Chinese nationals crossing illegally at the southern border, a single-year surge confirmed by CBP and reported by NBC News that exceeded the combined totals from multiple prior years. Earlier years saw smaller numbers, and fiscal year 2024 added several thousand more, placing total Chinese encounters across the Biden era well into the 45,000 to 50,000 range. China is not a failed state. It is a strategic adversary with sophisticated intelligence services and leverage over citizens abroad. At this scale, illegal entry outside the visa system creates unavoidable counterintelligence exposure, not because intent can be assumed, but because visibility is lost when volume overwhelms screening. What unites these figures is not suspicion about migrants themselves, but uncertainty. In many cases, we do not know who these individuals truly are beyond what they claimed at entry, why they came when they did, or who they may now be affiliated with. Many arrived from environments where identity documents are incomplete or controlled by militias, where criminal and intelligence records are inaccessible, and where affiliations can change after arrival. A one-time screening at the border cannot resolve that, and once released into the interior, there is no scalable mechanism to revisit those questions over time. ICE’s stepped-up enforcement in 2025 addresses part of the picture. Arrests increased. Detention reached record levels, with more than 68,000 individuals held at one point, the highest number ever recorded, a figure documented by The Guardian. But deportations, however necessary, do not retroactively solve the visibility gap created by the Biden-era intake. The danger left behind by the surge is not hypothetical. It is present, embedded, and largely unquantified. After 11 million illegal entries, the United States is no longer confronting only a border problem, but an interior intelligence problem, one defined by the unknown. We do not reliably know who a significant portion of this population is beyond initial claims, why they came when they did, or how their affiliations, beliefs, or vulnerabilities may have evolved since arrival. What makes this moment dangerous is scale. Risk at the margins can be managed. Risk measured in the millions cannot, not with episodic enforcement, not with static screening, and not with systems built for a different era. Threat develops quietly, often long after entry, through ideology, networks, and influence. This is not an argument against enforcement. It is an argument for matching enforcement with intelligence at scale. ICE can remove violators. Border Patrol can interdict flows. But neither can answer the central question left behind by the surge: what risks are already here, unobserved and unmeasured. The most permissive period in modern border history did not just change who came in. It changed where the risk now resides. It is no longer only at the border. It is within. And until the United States builds the capacity to see it clearly, risk at this scale will remain the country’s most dangerous unknown. READ MORE from Kevin Cohen: Britain’s Boat Crisis Comes Into Focus Age Fraud and the Collapse of Child-Only Safeguards Hollow Sanctuaries: When Churches Become Mosques