Nearly 100,000 people were taken into custody along the southern border in April after illegally crossing from Mexico into the United States, marking the highest number in one month since April 2007, according to new federal data.

Department of Homeland Security numbers show U.S. Border Patrol agents in Texas, New Mexico, Arizona, and California apprehended 98,977 people who crossed between ports of entry in areas that do and do not have barriers.

A total 109,144 people were encountered at the border in April. On top of the 99,000 unauthorized crossings, another 10,000 people attempted to pass through border crossings but were turned away.

Roughly 60% of that figure — 58,474 — were families and 9% — 8,897 — were unaccompanied children. The remaining 31,606 people arrested were single adults, likely unable to claim a credible fear of return and apply for asylum like the families.

April's numbers are up from 103,000 in March — 92,600 people who illegally crossed the southern border and nearly 11,000 people encountered by federal police approaching ports of entry but turned away, including asylum seekers.

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U.S. Customs and Border Protection

The number of people who were taken into custody for attempting to enter between border crossings nearly doubled from approximately 46,000 in January. They had dropped significantly during the first few months President Trump was in office, down to less than 16,000 illegal entries and turn aways at ports of entry.

However, those numbers have shot up since October. Customs and Border Protection officials have blamed human smugglers for flooding certain parts of the border with migrants and said those paying up to $8,000 to get to the U.S., primarily from Central America, are doing so because they know they will not be held in federal custody for more than a few weeks, due to U.S. policies.

Customs and Border Protection, the parent agency to Border Patrol, said the number of people being turned away at official border crossings has remained consistent in recent months, but the number of families traveling to the U.S. from Central America continues to rise.

In the first six months of the 2019 fiscal year, the number of people who arrived at the border with a family member was up 370% from the same period a year ago. Around 60% of all people who illegally crossed in fiscal 2019 were families compared to the 1990s and 2000s when the large majority were single adult men from Mexico who re-entered several times in a year.

U.S. Customs and Border Protection

In fiscal 2019, more than 100 groups of 100 or more people have shown up at the border, crossing at spots of the 1,900 mile-long boundary that have little or no fencing.

In fiscal 2017, Customs and Border Protection documented two groups of 100 people or more. The number of group apprehensions jumped to 13 in 2018.

The Rio Grande Valley of eastern Texas; the El Paso Sector, which includes all of New Mexico; and the Tucson region of Arizona have seen the most apprehensions since October.