Yep, Arthur was another Usurper.
And as the State Department says currently,
https://fam.state.gov/FAM/08FAM/08FAM030101.html#M301_1_1
[State Department, Foreign Affairs Manual]
(a) Acquisition of U.S. citizenship generally is not affected by the fact that the parents may be in the United States temporarily or illegally; and that; and(b) A child born in an immigration detention center physically located in the United States is considered to have been born in the United States and be subject to its jurisdiction. This is so even if the child’s parents have not been legally admitted to the United States and, for immigration purposes, may be viewed as not being in the United States.