Quite an Interesting Read, this article is 13 years old:

Liberty And Immigration
by Thomas E. Woods, Jr. for the Foundation for Economic Education

The extraordinarily high rate of immigration, legal and illegal, into the United States is an indication that our country is doing something right. The United States, while far from boasting a pure free market, clearly offers enough economic liberty to attract the migration of peoples from all over the world. Currently, half the world's immigrants come to the United States.

Libertarians have generally welcomed immigration, and on very simple grounds. According to the “non-aggression axiom,â€