According to preliminary Customs and Border Protection numbers for January obtained by CNN but not yet released to the public, family unit apprehensions decreased by 42%, unaccompanied minors were down 39% and total apprehensions decreased by 27%.
Month-to-month numbers in apprehensions can be misleading. According to data for the past four years, apprehensions typically drop in January and did so sharply in 2016.
Next month's data could be critical in interpreting whether the drop was due to seasonal trends or something bigger. The amount of migration north through Mexico is also tied to the conditions in Central America, where many migrants are fleeing violence and drug cartels.
The numbers also do not take into account what are called inadmissables -- migrants who present themselves at the border and are deemed unable to enter the country, often due to lack of authorization. Apprehensions refer to those removable aliens who are arrested.
Still, Trump supporters are likely to see the numbers as vindication of his hardline approach to immigration, an indication that his tough talk and policy proposals are already deterring migrants from coming in.
While total and unaccompanied minor apprehensions had been trending downward last month already, family units surged in the final three months of 2016 -- a statistic that Trump supporters interpreted as an attempt by desperate migrants to get into the US before Trump was inaugurated and could change US immigration policy.
As Trump continues to roll out his executive agenda and as Congress begins to consider how they will pay for his promised wall and increase in enforcement, the numbers could provide key talking points in the push to implement Trump's immigration agenda.
There were 9,314 family unit apprehensions in January, down from 16,135 in December; 4,430 unaccompanied minors apprehended, down from 7,243 in December, and 31,575 total apprehensions, down from 43,272 in December.
In 2016, total apprehensions were 37,014 in December 2015 and 23,758 in January 2016, a drop of 36%, according to CBP data
Family units dropped
from 8,973 to 3,143 from December 2015 to January 2016, a dip of 65%, and monthly data for unaccompanied minors was not readily available.
The numbers could shift slightly when they are released to the public, as CBP regularly revises its statistics pending agency reconciliation of individual records.
The White House referred questions to the Department of Homeland Security, and CBP declined to comment until they release final numbers