U.S. Census Bureau -- Foreign Born Population
The U.S. Census Bureau uses the term foreign born to refer to anyone who is not a U.S. citizen at birth. This includes naturalized U.S. citizens, lawful permanent residents (immigrants), temporary migrants (such as foreign students), humanitarian migrants (such as refugees), and people illegally present in the United States.
The Bureau provides a variety of demographic, social, economic, geographic, and housing information on the foreign-born population in the United States.
U.S. Dept. of Justice -- Executive Office for Immigration Review
Includes data on immigration court proceedings, decisions, appeals, asylum cases, etc.