There really isn't a difference . I guess one is political and the other is accurate? Both are still violations of the law so yeah there is no difference. Hope this helps!
Legal immigrants are foreign-born people legally admitted to the U.S. Undocumented immigrants, also called illegal aliens, are foreign-born people who do not possess a valid visa or other immigration documentation, because they entered the U.S. without inspection, stayed longer than their temporary visa permitted, or otherwise violated the terms under which they were admitted.
