Two Important Notes:
Congress, and only Congress, enacts laws at the federal level.
Federal executive departments and administrative agencies write federal regulations to implement the authority of laws. Regulations (as well as Executive Orders and Proclamations) are ancillary or subordinate to laws, but both laws and regulations are enforceable.
official chronologic compilation of all laws
U.S. Code of Federal Regulations (CFR)
official compilation of codified regulations by subject
consists of two publications and should be used together to find the latest version of a regulation: the annually revised Code of Federal Regulations (CFR) and the daily Federal Register (FR)