According to leaked CBP data, U.S. authorities encountered 14,509 migrants at the U.S.-Mexico border yesterday (December 18). That’s probably about 13,000 Border Patrol apprehensions between ports of entry (official border crossings) and about 1,500 people reporting to the ports of entry, nearly always with appointments made using the “CBP One” app.

That’s almost certainly the largest number of migrant arrivals at the U.S.-Mexico border in any day since at least 2000.

Aaron at the American Immigration Council says this increase, which seems to have begun in November, “is driven partly by rumors that the border will close soon and the CBP One app will be shut down.” That may explain it. A funding crisis at Mexico’s migration agency (National Migration Institute, INM) could also be a factor.

This is really unusual, though, because migration data further south along the U.S.-bound migration route would lead one to expect the numbers at the U.S.-Mexico border to be declining. Panama, Honduras, and Mexico have been reporting fewer people coming after record-breaking levels in late summer and early fall.

Here’s Panama: a 24 percent decline in migration through the Darién Gap from October to November, and a 50 percent decline in migration from September to November. So, fewer people departing the South American continent.

Data table

Here’s Honduras: down 41 percent from October to November. So, fewer people coming from South America and through the increasingly used aerial entry point in Nicaragua.

Data table

And here’s Mexico: down 4 percent from September to October (Mexico, like the United States, has not reported November yet).

Data table

Why are the numbers up so much at the U.S. border when they’re down everywhere else along the route? The answer probably has to do with:

• A jump in migration from citizens of Mexico and Central American, and/or
• Crossings of Venezuelans and others who had arrived in Mexico more than 1-2 months ago, and perhaps are now giving up on waiting for CBP One.

Also, If recent Decembers are a guide, the U.S. border numbers could be on the verge of dropping. The first halves of December 2021 and December 2022 saw very heavy migration, capping off growth that accelerated all fall (as did the fall of 2023). Numbers dropped during the second halves of those Decembers, as the holidays approached.

Data table