Illegal immigration has been a problem for the United States for a long time. This phenomena is not new and thousands of illegal immigrants have come into US through either the Mexico border, the Pacific Ocean, or through many other ways. Some people have entered the country legally through a visit visa, but then have stayed illegally and are working in various places. Illegal immigration is a double edged sword; on the one hand it provide the local economy with cost benefits as the illegal immigrants are not paid so much, while they are more productive. On the other hand, these illegal immigrants do not pay taxes and their employers also do not pay their taxes. There are both pros and cons of illegal immigration and this paper shall take a look at some facts pertinent to illegal immigration in the United States.