For years now, "illegal immigration" has been nearly synonymous with "Mexico." You don't see Canadians sneaking over the northern border into the U.S., say some folks, but boy, oh boy, are there loads of Mexicans storming the southern one.
It's true that Mexico is the country of origin for most of America's unauthorized immigrants; in 2014, 49 percent of all undocumented residents hailed from that country. But the number of Mexican immigrants in the U.S. illegally has declined from 6.9 million in 2007 to 5.6 million in 2014. And a first: In 2014, more non-Mexicans were nabbed at the southern border than Mexicans, according to the Pew Research Center [sources: Gonzalez-Barrera and Krogstad, Krogstad and Passel].
Which other countries are represented? After Mexico, the next top four countries of birth for unauthorized immigrants were Guatemala, El Salvador, Honduras and China. Overall, from 2008 to 2012, 3.3 million immigrants came into the U.S. illegally — 13 percent from Asia; 7 percent from South America; 4 percent from Europe, Canada (yes, Canada!) and Oceania; 3 percent from Africa; and 2 percent from the Caribbean [source: Zong and Batalova]. And many people who are here illegally overstayed tourist or student visas.