Code of Federal Regulations (CFR): The CFR is the codification of the general and permanent rules published in the Federal Register by the executive departments and agencies of the Federal Government. The CFR is divided into 50 titles. The CFR is updated once each calendar year, and is issued on a quarterly basis. Each title is divided into chapters, which usually bear the name of the issuing agency. Each chapter is further subdivided into parts that cover specific regulatory areas.
The Federal Register: The Federal Register is the official publication for rules, proposed rules, and notices of Federal agencies and organizations, as well as executive orders and other presidential documents. It is published daily, Monday through Friday, except official holidays.
e-Code of Federal Regulations at eCFR
Current to within 2-3 days (no historic regulations)