The Canadians built a wall on the border between the United States and Canada. This plan was put in place by the new Canadian President. Herbert Garrison tries unsuccessfully to enter Canada so he can complain about all the refugees flooding South Park, but was stopped by a Canadian Border Wall Guard.
The New Kid is able to visit the wall after passing through Hillvale Farm, but they cannot get past the wall. The same guard from "Where My Country Gone?" will turn the New Kid away, while speaking to other Canadians at the other side of the wall.