Factual error: After the Oklahoma City casino incident, it shows a brief scene where Pierce picks up Dr. Rice. The sign in the background says "Ada 15, Oklahoma City 90" on Highway 81. That highway in Oklahoma is, in fact, a real road but it is no where near Ada. The closest area that is 90 miles from OKC would be around Duncan, which is well over 50 miles from Ada. (01:06:20)
Factual error: Logan and Laura emerge from an urgent-care clinic in a small town, presumably somewhere in the Great Plains or eastern Rockies. Shortly after they emerge from this clinic, a Louisiana state highway sign is visible in the background. As the scene ends, the camera pulls back to show mountains in the background, indicating that they aren't in Louisiana.
Factual error: The climax of the movie is set near the US-Canadian border. However, the landscape is very arid and desert like, similar to the Southwestern US. No such landscapes exist anywhere near the border with Canada.
Factual error: When Logan and Laura are driving towards Canada, they are supposed to be somewhere in Oklahoma. However, there is a shot of a mountain range in the background. Those are the Sandia Mountains, which are in New Mexico.
Answer: Dr. Rice tells Logan the mutants have been wiped out due to a drug in the food and water supply that suppresses mutations, thus no new mutants had been born in 25 years. In the film series, it's indicated mutant powers usually come out during puberty, so parents don't know their children are mutants until around 12 or 13. So it took over a decade to realise no new mutants had been born. However, the government had been breeding mutants for weapons, which is where the mutant children come from in the Logan film. Furthermore, it is implied the "Westchester Incident" was an uncontrolled seizure of Charles Xavier that resulted in the death of many of the mutant students.
Bishop73