Can You Make a Citizen's Arrest of Someone Who is Here Illegally?

Answer 1

I don't know of any court cases that have addressed this question.

The thing about citizen's arrest is that it is generally raised as a defense to claims of false imprisonment or battery, given that making the 'arrest' means performing conduct that is criminal and/or tortious.

Most immigration violations are misdemeanors, so they do not rise to the level of dangerous felonies that most states require before citizens are allowed to arrest people. Also, the federal govt has near-exclusive authority over immigration issues, so even local or state police have very little ability to arrest or hold people based on alleged immigration violations.