Border officials encountered 11 million unauthorized migrants attempting to enter the US between October 2019 and June 2024.

Data on these border encounters — which include people attempting to enter the country or apprehended trying to cross the border without inspection — helps the government estimate the number of individuals illegally entering the US.

By understanding the demographics and origins of people encountered at the border, policymakers can better understand the complex factors driving immigration and make informed policy decisions.

What is a border encounter?

The Department of Homeland Security separates border encounters into three categories:

  • Apprehensions are people temporarily detained by the US Border Patrol (USBP) for crossing the border illegally between ports of entry. They may or may not be arrested under Title 8 and can file for asylee status.
  • Inadmissibles are people seeking legal admission at official ports of entry who are found ineligible by officers of the Office of Field Operations (OFO) under Title 8. This category also includes people seeking humanitarian protection and people who voluntarily withdraw their admission application; they can also file for asylee status.
  • Expulsions are migrants denied exclusively through Title 42 to stop the spread of COVID-19. This status only applied from March 2020 to May 2023. USBP or OFO officers were empowered to expel people and return them to their home country or last non-US location. These individuals were not given the opportunity to apply for asylum.

These encounters don't necessarily reflect the actual number of people trying to cross the border; some people make multiple crossings during the same fiscal year, meaning they’d appear more than once in the data, and others successfully enter without encountering any US official.

How many border encounters occur each year?

Between October 2019 and June 2024, US Customs and Border Protection (CBP) reported just under 11 million border encounters nationwide. That’s roughly equivalent to the current population of North Carolina, the ninth most populous state.

Monthly encounters peaked with over 370,000 people in December 2023. That month, CBP encountered nearly 12,000 people at the border every day. That's more than eight people every minute.

December 2023 encounters were approximately 70% of the total encounters in 2017 (which was around 527,000).

As of June 2024, the last month of available CBP data, there were 1.44 million reported border encounters in 2024.

The US averaged over 1.3 million border apprehensions a year during the 1990s compared to less than half a million during the 2010s.

Attributing the fluctuations in border encounters and migration to the US over time isn’t an exact science, but much of it comes down to push and pull factors.

Push factors are negative circumstances that drive people out of their countries of origin, like violence, insecurity, and famine in places like Guatemala, Honduras, and El Salvador. Pull factors are circumstances that make migrating enticing, including a strong economy, weak points in immigration enforcement, and a market for transnational smugglers who promise entry to the US.

How many people illegally cross the border?

While there isn’t any definitive data on unauthorized immigrant numbers — there’s no way to know how many people entered the US without an encounter — border encounter numbers serve as a helpful if imperfect proxy. The at-the-border apprehension rate helps the Office of Immigration Statistics model what proportion of illegal entries are prevented by apprehensions.

Despite the relatively high number of encounters in 2021, the CBP’s estimated at-the-border apprehension rate averaged 78% from 2018 to 2020, compared to 35% from 2002 to 2004. This resulted in fewer entries without inspection than in the early 2000s.

The higher number of border encounters in recent years may be attributable to high apprehension rates, meaning that border patrol operations are working more efficiently, preventing a higher percentage of people from entering the country without authorization.

Read the full article about U.S. border crossings at USA Facts.