We took a look at some of the demographic breakdowns of the group pulled together by the Pew Hispanic Trends Project and the Department of Homeland Security.
Here is what we found:
1. Illegal immigrants make up 3.5 percent of the U.S. population
The vast majority of the population has roots in North America -- particularly Mexico and Central America. China, the Philippines, Korea and Vietnam are among the top 10 countries of origin for the Asian illegal immigrant population, which has remained stable at 1.3 million -- about 11 percent of all undocumented immigrants.
2. Declining numbers from Mexico
The population of unauthorized immigrants over the last 4 years has largely flat-lined, remaining stable. Yet the Mexican undocumented population, which is 52 percent of the total, has consistently declined. Partly it's the difficult economy, which hasn't fully recovered, and a more secure border. And President Obama, nicknamed the "deporter-in-chief" by some, has been aggressive at sending people back to their country of origin -- more than two million to date.
3. Unauthorized immigrants are settling in the South
President Obama began the public push for his executive order in Nevada, but while that state does have a high Latino population and the highest percentage of illegal immigrants in the country, it doesn't make the top 10 of states as far as total undocumented population. (Roughly 210,000 undocumented immigrants live in Nevada.)
This list, which is mostly made of blue states, isn't exactly surprising. Georgia and North Carolina are part of a more widespread Latino population boom in the South. Relative to the overall population, Latinos -- undocumented and otherwise -- make up a small share. But their growth is rapid, doubling in some states in recent years.
4. Well over half of the illegal immigrant population arrived after 1995
Obama's executive action will cover people who have citizen or legal permanent resident children who have been here for at least five years, meaning 2009 or before. His move will also expand the time frame use for the Deferred Action for Childhood Arrivals (DACA) measure to include any children who were brought to this country illegally before 2010.
5. The population is very young
Back in 2012, during a GOP presidential debate, Newt Gingrich and Mitt Romney sparred over deporting "grandmothers and grandfathers," zeroing in a demographic that is actually a very small part of the illegal-immigrant population. Some 80 percent are 44 years old and under, meaning they have a number of working and childbearing years in front of them. This means an expanded tax base for those that get work permits, but also means that in some instances people live "off the grid," while still utilizing school systems and hospitals.
6. Illegal immigrants make up a 5.1 percent of the workforce
Because of that youth, illegal immigrants are over-represented in the workforce -- 5.1 percent versus 3.5 percent of the overall population.
During his speech announcing his executive order, Obama made several references to illegal immigrants roles in the workforce. He talked about "workers who pick our fruit and make our beds" and "the determination of immigrant fathers who worked two or three jobs without taking a dime from the government." Dating back to 1995, as their population rose, illegal immigrants have steadily joined the workforce, peaking in 2011. The parents of lawful permanent residents and citizens who have been here for more than five years will be able to apply for work permits and temporary relief from deportation.
7. 7 percent of k-12 students have an undocumented parent
Another are where the undocumented are over-represented versus their share of the population is as parents. In fact, 7 percent of non-college students have at least one parent who is undocumented.
Obama talked a lot about students in his speech, acknowledging "the courage of students who, except for the circumstances of their birth, are as American as Malia or Sasha; students who bravely come out as undocumented in hopes they could make a difference in the country they love." And it's no accident that he will give his first speech outside of the beltway at a school in Nevada, where 17.7 percent of school children have a parent who is an illegal immigrant.