10. Colombia
Undocumented population: 137,000
Colombia gained international infamy after Pablo Escobar successfully made the country a hub for the production and smuggling of cocaine, a move which saw laws and regulations in the country defiled by the cartels, making it a dangerous place to live in while providing impetus for the residents to leave the country in order to save their lives. Colombia has now become a hub for human smuggling, and while many Colombians have moved to the US illegally, people from other countries also enter the US illegally through Colombia.