For libertarians, immigration can be a controversial question.

Most libertarians consider that governments should not have any authority on deciding who can go where. However, they also consider that individuals have the right to forbid people to trespass through their private property, and that ultimately, all land should be private property.

The controversy is thus mostly among libertarians interested in governmental policy, assuming government exists (independently of whether it should or not): what should governments do in absence of a free market for immigration? Some libertarians argue that because government is so deep into plunder via welfare-state, people who would increase plunder shouldn't be allowed to immigrate, or that since there are some kinds of immigrants that would be rejected even without excessive government intervention (be it only an invading foreign army), then government must at least reject these immigrants, since it has taken the responsibility to control immigration. Many libertarians think that the question is irrelevant to them, and that their purpose is to limit government: if welfare state is incompatible with free immigration, then welfare state should be abolished, rather than immigration regulated.

Anarcho-capitalists will even argue that if some immigrants must be refused, then the means to do that should be returned to all citizens, instead of being monopolized by the government. In any case, Anarcho-capitalists might differ as to what they think the final outcome would be regarding immigration, but agree that the optimal answer would emerge from a free market in justice and protection.