ICE are anywhere in US. Border patrol are within 100 miles of a border.
Border Patrol was set up in the 1920s, ICE after 9-11.
I find it interesting because I think Bush set up ICE because of terrorism. He wanted a nationwide force to be able to check papers etc, arrest and deport. The whole immigration thing appears to be one of these GOP manufactured " problems" that was never really a problem. Prior to ICE, cross the southern border and get caught within 100 miles and you got put on a bus and sent back. Get 100 miles away, and you were pretty safe. Unless you done a crime and the cops caught you.
The farms/ meat packers/ hospitality etc needed migrant workers. The economy needed them, and still does. And South Americans crossing back and forward just wanting to work and make money to send/take home was not an issue. They were needed. So long as they kept their nose clean and head down.
But ironically, once the Repugs said " Hey, this is an issue, a big problem" ( a vote winner), and the migrant back and forward was defined as " not good", people started to claim asylum.
More complex than that of course, and I am happy to be corrected. But I think that at it's basic level, it was a manufactured policy. Same as abortion, and now the culture wars.