Immigration has a few negative effects on the United States, including the use of government services without tax deductions as illegal immigration brings undocumented workers, adding to overpopulation in cities and hurting Americans by competing with them for jobs. Some people argue that undocumented immigration workers are actually able to help the economy because they are competing for jobs that Americans do not want; however, Americans without high school diplomas or without college degrees are often interested in the lower-skill and lower-wage jobs also.
It is impossible to determine whether immigration is beneficial to the country at large because there are many factors to consider, and these factors change year to year. As of 2014, there are more than 12 million undocumented immigrants in the U.S., and while their impact on the economy may be seen as negative as well as positive, it is difficult to determine the overall effect.
It seems that immigration hurts the people born in the U.S. who are from low-income families. A lack of education or financial means often results in these people having a small skill set, seeking low-wage jobs, such as janitors and cashiers.