Federal and state regulations differ from statutes in the types and amounts of background materials available for research. In general, "regulatory intent" can be determined from the preambles of a final regulations published in the Federal Register or a state register. Agency intent and responses to public comments are also determined by examining differences between proposed and final regulations. Federal regulations are published first in the daily Federal Register. Final rules are edited and codified by agency and topic in the Code of Federal Regulations (CFR). However, the Federal Register contains information that is not transferred to the CFR, including notices of proposed rulemaking, agency policy statement, discussions of comments submitted by the public, and notices of agency actions.
A Research Guide to the Federal Register and the Code of Federal Regulations, Richard J. McKinney, Federal Reserve Board (LLSDC 2016).
How to Trace Federal Regulations - A Research Guide, Barbara Bavis & Anne Guha, In Custodia Legis (blog of the Librarians of Congress) (2014).
Legal Research Process: How to Compile a Regulatory History, Tarlton Law Library, University of Texas School of Law (frequently updated).
RegInfo.gov - lists all rules currently under regulatory review, and provides a list of rules on which review has been concluded in the last 30 days; includes lists, regulatory reviews, and letters to agencies regarding regulatory actions back to 1981.
Regulations.gov - federal website allowing the public to make comments on proposed regulations quickly and conveniently. Search by title or topic to find relevant regulations, proposed regulations open for comment with due dates, read comments submitted by others, and find supporting and related materials.
Federal Register: Agency List (National Archives & Records Administration).
Counting Regulations: An Overview of Rulemaking, Types of Regulations, and Pages in the Federal Register, Maeve P. Carey, Congressional Research Service (Oct. 4, 2016).