USC Title 8 is the primary source for U.S. law on immigration. It is based on the following laws:
The Immigration and Naturalization Act of commonly used by practitioners rather than the U.S. Code. You can cross reference the INA to the USC.
After regulations are published in the Federal Register, they are collected and published in the Code of Federal Regulations, commonly referred to as the CFR. The CFR is arranged by subject title and generally parallels the structure of the United States Code. Thus, Title 8 of the CFR deals with "Aliens and Nationality", as does Title 8 of the U.S. Code.