As reported by Wikipedia: "The United States Department of Homeland Security (DHS) has estimated that 11.4 million unauthorized immigrants lived in the United States in January 2012." To the uninitiated or for those that are just waking up from a Rip Van Winkle sleep, the number of illegal immigrants present in this sovereign nation is absolutely stunning, almost unfathomable. After all, the United States spent within the last decade over $2 billion dollars on border fencing and has over 21,000 border patrol agents to patrol our borders, yet somehow or other, millions of illegal immigrants have migrated to America and live and work amongst documented Americans.
The top four countries that illegal immigrants originate from are all Spanish speaking, of which, by far, the country that provides the most illegal immigrants to America is Mexico. There are a lot of questions to be asked about why there are so many illegal immigrants in America, but most of the answers to those are rather intuitive or become rather obvious after any sort of thought. For instance, although America at the federal level does not have an officially designated language, it is quite obvious that if it was to declare one, that it would be English. Yet, strange to say, calling just about any customer service agency in America from any place within America, will almost invariably give the caller the option of hearing instructions or information in either English or Spanish. The reason that this is so is because America has an incredible amount of immigrants, legal, illegal, permanent residents, and those granted amnesty to which their first language is Spanish, to which, quite clearly, being able to communicate utilizing their language of preference makes everything easier.
The next question of interest, would be, once someone has crossed the border somehow, they have to find means of employment, housing, and so forth, to which with all the identification rules, laws, and policing that America has, would appear to be quite formidable. The answer to that particular puzzle is to understand whether in war or peace, that there is always and always will be an "underground railroad" or similar, to which all it takes is citizens or businesses that out of humanitarian concerns, or for self-serving economic reasons, or for various other reasons, feel a need to help, abet, and support illegal immigrants in their quest for the American dream.
The fact of the matter is, that hotels need housekeepers, restaurants need dish washers, cooks, and janitorial services, dual working families need both maids as well as nannies, construction sites need cheap labor in order to be competitive, agricultural interests need hands in the fields, and so on, to which each of these industries in one way or one form or another, have a need that an illegal immigrant can easily fill, and usually at a much lower price point than legal domestic labor. This means that these businesses and personal interests have a vested interest in illegal immigrants being part and parcel of this land, and thereby the local governing authorities not wanting to upset what already works and is common knowledge, for the most part, allows it to be.
Then there is the fundamental question, as to how do so many illegal immigrants actually successfully cross the border to begin with, and the most basic answer to that question is that there are now and always have been powerful vested interests that make sure to accommodate policing and governing authorities so as to permit the crossing of these immigrants into our nation. The bottom line is that the sheer number of illegal immigrants in this country can only mean that these illegal immigrants are strongly desired by influential and important people in conjunction with business interests for their benefit, and until such a time as those interests dissipate, the number of illegal immigrants and those needs will not materially change.