From: The Federation for American Immigration Reform
Illegal aliens come to the United States to take jobs that offer them greater opportunity, and they are often welcomed by U.S. employers who are able to hire them for wages lower than they would have to pay to hire U.S. workers. This employment is illegal under a law enacted in 1986, but some employers ignore the law and hire illegal workers in the underground economy. Others simply accept fake employment documents and hire the illegal workers as if they were legal. Because there is no requirement to verify documents presented by workers, employers can easily evade compliance.
The illegal alien workers are mostly persons who sneaked into the country — nearly all Mexicans or Central Americans who enter from Mexico. There is also, however, illegal entry across the border with Canada, with apprehensions by the Border Patrol of more than 6,000 aliens in 2010. There is also a significant portion of the illegal alien population that arrives with visas and stays illegally. These ‘overstayers' are estimated variously to between one- third and 40 percent of the illegal alien population.
The defenders of illegal aliens — ethnic advocacy groups, employer groups, and church-based groups — often assert that illegal aliens only take jobs unwanted by U.S. workers. This is patently false because they are working in jobs in which U.S. workers are also employed — whether in construction, agricultural harvesting or service professions.
FAIR's estimate of the number of illegal aliens in the Rhode Island workforce as of March, 2013 – 25,075.