These checkpoints can be up to 100 miles inside the border. Their frequency went up in the years after 9/11, then diminished, but they are still going on. Due to their locations, they are usually stopping people who never crossed a border.
<<Gilles Bissonnette, legal director of the ACLU of New Hampshire, said the the interior checkpoints are being used “as a ruse to unlawfully search and seize people for the purpose of general crime control.”>>
read more at: https://www.seacoastonline.com/news/20200811/lawsuit-challenges-use-of-checkpoints-miles-from-border