Federal regulations are written by executive agencies to enforce the statutes passed by Congress. They have the force of law, and provide detailed instructions on how agencies intend to enforce laws. In the same manner as federal laws, federal regulations are published in 2 ways and are available in print and electronic form:
The Federal Register [FR]
The chronological version of new regulations, proposed rules, and notices from federal agencies
The Code of Federal Regulations [CFR]
A codified version of regulatory law (arranged by topic) with all obsolete rules removed.