Even worse, technically, the 'border' extends 100 miles inland within the United States. Your rights are extremely limited in these areas: https://www.aclu.org/know-your-rights/border-zone

If you've ever lived in, visited or traveled through some areas of the American south, you may be surprised to find border checkpoints 80 miles north of the US/MX border, for example. Borders aren't just land borders, either, as it also includes sea/lake borders.