Apprehensions of people trying to cross the southern border peaked most recently at 1.6 million in 2000 and have been in decline since, partly because of technology upgrades, tougher penalties post-9/11, a decline in migration rates from Mexico and a sharp rise in the number of Border Patrol officers.
Customs and Border Protection reported 303,916 apprehensions at the U.S.-Mexico border for fiscal 2017, the lowest in more than 45 years. In fiscal 2018, apprehensions increased to 396,579, but that was less than half the total of 2007.
There are far more cases of travelers overstaying their visas than southwest border apprehensions. In fiscal 2016, U.S. officials reported 408,870 southwest border apprehensions and 544,676 suspected in-country overstays. For fiscal 2017, the Department of Homeland Security reported 606,926 suspected in-country overstays, or twice the number of southwest border apprehensions.