The facts behind the high number of migrants arriving at the border under Biden

The soaring number of migrant arrivals along the U.S. southern border over the past year and a half has fueled dire humanitarian challenges, strained government resources and created a political liability for President Biden.

In some ways, the migration flows across the U.S.-Mexico border during the Biden administration are unprecedented. Arrests of individuals who crossed the U.S. southern border illegally have reached all-time highs. Arrivals of migrants from certain countries, including Cuba and Venezuela, have set new records.  

But by other measurements, including overall illegal entries, the latest migration wave is not unprecedented. 

Despite the recent record levels of migrant arrests, there were more unlawful entries in the mid and early 2000s, when the U.S had fewer resources and personnel to apprehend border-crossers, according to government data obtained by CBS News. An unusually high rate of repeat crossings during the coronavirus pandemic has also inflated the border arrest tallies.

Here are the facts about arrivals of migrants along the U.S.-Mexico border during the Biden administration.

Border arrests have reached record levels

Border Patrol, an agency within Customs and Border Protection (CBP), apprehends migrants who enter the U.S. illegally in between ports of entry. The Office of Field Operations, another CBP agency, facilitates commercial, pedestrian and other forms of lawful traffic, while processing migrants who seek asylum at ports of entry, which is legal under U.S. law.

In fiscal year 2021, which included Mr. Biden's first eight full months in office, Border Patrol recorded 1.66 million arrests along the southern border, surpassing the previous all-time high of 1.64 million arrests set in 2000, CBP data show.

During the first 10 months of fiscal year 2022, Border Patrol agents along the Mexican border reported more than 1.8 million apprehensions, a new record high that will likely surpass 2 million when fiscal year 2023 starts in October, according to the CBP figures.

These figures do not include migrants processed at ports of entry along the southern border, where the Biden administration has processed some migrant groups, including Ukrainian refugees, those returned to Mexico under discontinued Trump-era rules and asylum-seekers determined to be vulnerable.

In fiscal year 2021, 75,000 migrants were processed by the Office of Field Operations at ports of entry along the Mexican border. That number has climbed to 130,000 during the first 10 months of fiscal year 2022.

An unprecedented demographic shift 

Before the early 2010s, the vast majority of border-crossers taken into U.S. custody were from Mexico, typically men without children traveling in search of work.

That trend shifted in subsequent years when migrants from Guatemala, Honduras and El Salvador started journeying north in greater numbers. The number of families traveling with minors and unaccompanied children seeking asylum also increased dramatically, peaking in 2019, under former President Donald Trump.

The pandemic reversed that trend. Single adult migrants again became the bulk of those taken into U.S. custody, comprising 64% of Border Patrol arrests in fiscal year 2021 and 71% of arrests so far in fiscal year 2022, up from 35% in 2019, according to CBP figures.

Another seismic demographic shift recorded under Mr. Biden is the growing share of migrants from countries outside of Mexico, Guatemala, Honduras and El Salvador entering U.S. border custody. Record numbers of Cubans, Venezuelans, Nicaraguans, Colombians, Haitians and other nationalities have been processed by U.S. border officials in the past year and half.

While Border Patrol apprehensions involving migrants from countries beyond Mexico and Central America's Northern Triangle stood at 9% in fiscal year 2019, they jumped to 22% in 2021 and to 40% in 2022.

But many migrants have been quickly expelled

Since March 2020, U.S. border agents have used a public health law known as Title 42 to quickly expel hundreds of thousands of migrants to northern Mexico or directly to their home country without allowing them to request asylum.

In fiscal year 2021, 63%, or just over 1 million, of Border Patrol apprehensions resulted in migrants being expelled under Title 42, government data show. Nearly 50% of the 1.8 million Border Patrol arrests in the first 10 months of fiscal year 2022 turned into rapid expulsions to Mexico or migrants' home country.

Decisions to not expel migrants are based on different policy, logistical and diplomatic reasons. For example, as a policy matter, the Biden administration has not been expelling unaccompanied children, most of whom are instead housed in government shelters until they turn 18 or are placed with a sponsor in the U.S.

Other migrants are not expelled because of humanitarian reasons, such as an acute medical condition. And many border-crossers are not expelled because Mexico generally only accepts the return of its citizens and Central American migrants. The U.S. also cannot expel migrants to Cuba, Nicaragua and Venezuela because of frosty diplomatic relations with the authoritarian governments in those countries.

Migrant adults and families who are not expelled under Title 42 can be released with a court notice, sent to long-term Immigration and Customs Enforcement detention centers or deported under regular immigration procedures, including a fast-track deportation program known as "expedited removal."

And border arrests don't equal individual migrants

While 2021 and 2022 have set records for border arrests, Border Patrol apprehensions don't equate to individual migrants. For example, one migrant who illegally crossed the border three times in one month after being expelled to Mexico twice is counted as three apprehensions.

In fact, during the pandemic, the number of repeat crossers has grown exponentially as some migrants enter the U.S. multiple times after being returned to Mexico under Title 42, which does not come with the threat of multi-year banishments, detention or criminal penalties, unlike formal deportations.

After hovering below 15% in the preceding years, including at 7% in 2019, the Border Patrol recidivism rate jumped to 26% in 2020 and 27% in 2021, CBP data show. In fiscal year 2022, over a quarter of all Border Patrol apprehensions have involved migrants who had been previously arrested by the agency.

Undetected unlawful crossings were likely higher in the 2000s

Border Patrol apprehensions along the southern border in 2021 and 2022 have each surpassed the 1.64 million arrests the agency recorded in 2000, a figure that stood as the record high for two decades.

However, Border Patrol now has a significantly superior apprehension rate than in the early 2000s due to improved surveillance technology, more enforcement resources and thousands of additional agents.

In fiscal year 2000, Border Patrol was able to apprehend 43% of all border crossers, according to government estimates, which calculate that there were likely 2.1 million successful border crossings that year in which migrants evaded apprehension.

The Border Patrol apprehension rate has increased dramatically over the years, reaching 90% in 2019 and 66% in 2020. Detected and undetected unlawful border crossings that do not result in an apprehension have also plummeted, falling from over 2.1 million in 2000 to 200,000 in 2020, according to government calculations.

There were an estimated 660,000 successful unlawful border entries that did not end in an arrest in fiscal year 2021, according to unpublished DHS figures, which also show the apprehension rate for that year was over 70%. These figures include "got away" incidents of migrants who were detected but not arrested by Border Patrol, and estimates of undetected entries. 

The statistics suggest there were 2.3 million border crossings along the southern border in fiscal year 2021 (the sum of Border Patrol arrests and estimated successful illegal entries). That's a smaller figure than the estimated border crossings in 2006 and prior years, when successful unlawful entries hovered above 1.5 million. 

In fiscal year 2006, for example, there were likely over 2.8 million unlawful border entries. In 2000, meanwhile, there were approximately 3.7 million unlawful border crossings. The latter tally is one the total border crossings in fiscal year 2022 are unlikely to surpass, even with the record levels of Border Patrol arrests.