Code of Federal Regulations

The Code of Federal Regulations (CFR) organizes the body of administrative law produced by U.S. federal agencies under authority delegated by Congress. While statutes passed by Congress are codified in the United States Code (U.S.C.), the implementing regulations agencies adopt to carry out those statutes are codified in the CFR. Together they form the two principal sources of binding federal law in the United States.

The CFR is divided into 50 titles representing broad subject areas — for example, Title 7 (Agriculture), Title 17 (Commodity and Securities Exchanges), Title 21 (Food and Drugs), Title 26 (Internal Revenue), Title 40 (Protection of Environment), and Title 50 (Wildlife and Fisheries). Each title is subdivided into chapters (usually assigned to a specific agency), parts, and sections. Citations follow the format Title CFR Part.Section — e.g., 40 CFR 60.40 refers to a section of EPA's New Source Performance Standards.

Regulations enter the CFR through the rulemaking process governed by the Administrative Procedure Act of 1946 (APA). Proposed and final rules are first published in the Federal Register, the federal government's daily journal, after a notice-and-comment period. Once finalized, rules are codified annually into the CFR. The Office of the Federal Register, part of the National Archives and Records Administration, publishes both the Federal Register and the CFR in cooperation with the Government Publishing Office.

A continuously updated unofficial version, the electronic CFR (eCFR), is maintained online and reflects amendments as they take effect. The print edition is revised on a staggered annual schedule: Titles 1–16 as of January 1, Titles 17–27 as of April 1, Titles 28–41 as of July 1, and Titles 42–50 as of October 1.

For researchers, the CFR is essential for understanding how broad statutory mandates — such as the Clean Air Act or Dodd-Frank — are operationalized through specific, enforceable agency requirements.