CFR Parts Affected: Find Federal Register Rules

The short version

CFR Parts Affected is a finding aid for Federal Register rules and proposed rules that affect specific parts of the Code of Federal Regulations.

If you know the CFR title and part, such as 21 CFR part 101 or 40 CFR part 52, use CFR Parts Affected to find Federal Register rule documents that amended, or proposed to amend, that part. A proposed rule explains what an agency is considering and normally invites public comment. A final rule explains what the agency adopted and gives the effective date, compliance dates, or other timing details when those apply. Interim final rules and direct final rules can also amend the CFR, but you still need to read the Dates and Supplementary Information sections to understand comment rights, effective dates, and any conditions.

CFR Parts Affected is not a complete index of every notice that mentions a CFR part. Notices can still matter because they may announce hearings, reopen or extend comment periods, request information, or publish related agency actions, but most notices do not amend regulatory text. Use the official GovInfo CFR Parts Affected page for the finding aid, FederalRegister.gov for practical document search, and the linked official PDF or GovInfo record when legal reliance matters.

How to find rules by CFR part and date

Start with the CFR citation, narrow by publication date, then read the document type and Dates section before deciding what changed.

• Search the CFR title and part in GovInfo CFR Parts Affected or FederalRegister.gov. Add the agency, subject, docket number, RIN, or date range when the result set is large.
• Use document type filters to separate proposed rules from rules. FederalRegister.gov often labels final, interim final, direct final, and similar rule documents under the broader rule category.
• Open the document and confirm the CFR parts listed on the page. One rule can affect several parts, and a search result can mention a part without changing it.
• Read Action, Summary, Dates, and Authority. These fields tell you whether the agency is proposing text, adopting text, delaying an effective date, correcting an earlier rule, or acting under a specific statute.
• Use Regulations.gov when the Federal Register page links to a docket and you need comments, supporting documents, or the official place to submit a comment.

A CFR part number alone does not tell you whether the law changed today. The document type and the regulatory text do. Proposed rules are not binding final CFR text, but they are usually the public's main chance to comment before an agency decides what to adopt. Final rules are adopted agency rules, usually with an effective date that may be later than publication. Corrections can fix prior Federal Register or CFR text, and delays can move an effective date without rewriting the whole rule.

What the finding aid does and does not prove

CFR Parts Affected helps you find the Federal Register trail. It does not replace reading the rule or checking the current CFR text.

The daily Federal Register includes a list of CFR parts affected in that issue, and later daily issues in the same month carry a cumulative monthly list. GovInfo describes CFR Parts Affected as a way to find final and proposed rules that affect the CFR within a recent period or a date range. The separate List of CFR Sections Affected, or LSA, is a monthly Office of the Federal Register publication that lists proposed, new, and amended federal regulations since each CFR title's latest revision date.

For current codified text, check the CFR or eCFR after you identify the relevant Federal Register document. For the rulemaking record, check the docket. For deadlines, read the Dates section in the Federal Register document and confirm the docket instructions. Comment periods commonly vary by agency and rulemaking, so do not assume a universal deadline.

What to watch after you find a match

The hard part is not one search. It is knowing when the next document appears for the same CFR part, agency, docket, RIN, or topic.

For an active rulemaking, watch more than the part number. Agencies may publish a proposed rule, one or more comment deadline extensions, a hearing notice, a final rule, a correction, or a delay of effective date. The docket on Regulations.gov is where comments and supporting materials usually live when the rulemaking uses that portal. The publication record on FederalRegister.gov is where new Federal Register documents appear.

RegWatch is built for that ongoing watch. Create a free watch for a CFR part, agency, docket number, RIN, or topic, and it emails you when a matching Federal Register document posts. Start with one free watch, or use the RegWatch guides if you need help reading comment deadlines, effective dates, docket numbers, or RINs.