Do all undocumented immigrants or illegals sneak across the border?
Undocumented Immigrants At the Border
No. Although accurate numbers are hard to come by, approximately 40% of the over 11 million undocumented immigrants in the US originally came to the U.S. legally. For example, as tourists or some other non-immigrant or temporary visa. After the time expired for their stay they didn’t return to their home country. The moment they failed to depart they became “undocumented.”