Border security officials estimate the number of migrants apprehended or turned away at the southern border could reach 1 million by the end of 2019, according to a report by ABC News.
Federal officials estimate attempted crossings could top 95,000 in March and 100,000 in April, putting 2019 on track to reach numbers not seen in decades.
The number of migrants apprehended or turned away at the border rose sharply in February, after four months of relatively level numbers.
From October to January, roughly 60,000 people a month were apprehended or turned away at the border; in February, that number hit 76,103.
The official numbers for March have not been fully compounded or released yet — the Department of Homeland Security tends to release monthly statistics the second week of the following month — but reports indicate the upward trend seen in February will continue.
Still, it's unclear whether the sheer number of migrants attempting to enter the United States without prior permit has increased, or whether border officials are apprehending a larger proportion of them.
Over the past five years, and more markedly since 2017, Central American families have replaced single Mexican men as the bulk of border crossers.
Families tend to surrender themselves to Border Patrol or Customs and Border Protection officers to request asylum in the United States, while individual migrants in the past were more likely to attempt to enter the U.S. surreptitiously.
In 2000, the year with the highest number of apprehensions on record, 1.6 million immigrants were apprehended after crossing the border illegally. In March of that year, 223,305 people were apprehended by Border Patrol.
Apprehension and inadmissibility numbers have traditionally been used as an estimate of how many people are attempting to cross the border illegally.
But those numbers have been skewed by more effective border control and changes in migrant behavior, leading to a larger proportion of migrants being captured before they make it to the interior.
While the absolute number of migrants attempting illegal crossings may not be changing, the sheer number of apprehensions is overwhelming border authorities.
CBP officials did not immediately respond to a request for comment on this story.
CBP announced last week it would begin releasing migrant families with summons to appear in court rather than turning them over to Immigration and Customs Enforcement, as detention centers are at capacity.