But the 40,000 people taken into custody in September is less than one-third of the 132,000 arrests made in May at the height of a surge of illegal immigrants.

Roughly 40,000 people were apprehended after crossing into Texas, New Mexico, Arizona, and California during the month of September. That number was added to the previous 11 months to bring fiscal 2019, which ran Oct. 1, 2018, through Sept. 30, to slightly more than 851,000 arrests. Those arrested for illegally crossing into the U.S. from Mexico may have claimed asylum once in custody, but that figure is not released by the government each month.

The 851,000 arrested at the southern border does not include the number of people who approached ports of entry, or border crossings, to claim asylum or pass through but were turned away. U.S. Customs and Border Protection, the Department of Homeland Security agency that oversees these figures, is expected to release this and related data in a few weeks.