The laws enacted by Congress are interpreted and enforced through regulations published by various Executive branch agencies. These regulations, once published in the Federal Register, are collected in the Code of Federal Regulations (CFR). The CFR is organized by subject title, aligning with the U.S. Code (U.S.C.). While the Department of Homeland Security (DHS) is primarily responsible for immigration law enforcement, other agencies also play a role. For official regulatory content, consult the agencies or the Government Printing Office for the latest updates.