Originally Posted by
Fly-Me-to-the-Moon!
There are checkpoints inside the country away from the border. In Texas all major highways coming North have them 30-40 miles inland usually.
There is a checkpoint on IH-10 before El Paso but it is only in one direction and I don't recall now if it is East or West bound.
There are state Agriculture inspection stations in Arizona and California but they do not ask immigration status and are not 24/7.
Ciao,
FH