Level 1 Source - Easiest to read, links to additional pages in the sidebar on the right, but provides the least detail and doesn't always cite sources
Immigration: Moving Towards Hope, published by PBS
Level 2 Source - A bit more challenging, but provides sources like the U.S. Census Bureau
Myths and Facts about Immigrants and Immigration, published by the Anti-Defamation League
Level 3 Sources - Most challenging because it provides lots of questions and answers, questionable biases of creators
Facts about Immigration and the US Economy, published by the Economic Policy Institute
Frequently Requested Statistics on Immigrants and Immigration in the United States, published by the Migration Policy Institute
Other Sources of Interest
Infographic: The Screening Process for Refugee Entry into the United States, published by The White House
How do Syrian Refugees Get Into the US?, published by CNN