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Statutes: US and State Codes

Finding, interpreting and understanding U.S. statutes

Getting Started

What are statutes?

Statutes are laws enacted by a legislative body.  Statutes may also authorize administrative regulations and can overturn or modify court decisions that are sometimes concerned with statutory interpretation.  In the United States, both the U.S. Congress and individual state legislatures have the power to pass statutes. 

Remember: not all legal issues are governed by statute. Part of statutory research is determining whether or not a statute applies to a particular question or area of law. 

How Statutes are Published

Publishing Formats for Statutes

After a statute is passed by the legislature, it is published in three forms:

  1. Slip laws: individual pamphlets containing the text of a law as passed

  2. Session laws: annual compilations of laws passed in a legislative session

  3. Codes: compilations of the laws in effect, organized by subject

1. Slip Laws

Slip laws are the first version of a statute to be printed or appear online:

Slip laws may include:

  • statutory text
  • enactment dates (check headings and margins)
  • information about codification
  • information on legislative history materials, such as Senate or House reports. 

2. Session Laws

Next, slip laws from a single legislative session are collected and published in date order as session laws.

Session laws:

  • contain the complete text of laws exactly as enacted
  • are generally the most authoritative form of the law
  • generally control when there are differences in wording between the session law and the code*
  • are useful for historical research and tracing legislative histories

*but see the note on positive law codification below.

3. Codes

Codes organize the law and

  • answer the question "what is the law on a given topic, on a given date"
  • group related statutes on the same topic
  • incorporate amendments into the text of existing statutes
  • include references to the underlying session laws that have been incorporated into the Code

Codes come in different formats:

  • official (published by or with the direction of the state as the authoritative version) or unofficial (published without the state's direction, often by a commercial publisher, or by the state in a version not intended to be authoritative)
  • annotated (including summaries of relevant cases and cross-references to research sources) or unannotated (including only the statutory text) 

The United States Code

The United States Code (U.S.C.) is the official, unannotated code of the United States, and is published (in print) every six years with annual cumulative supplements.  As of 2022, the U.S.C. is divided into fifty-four major topics called titles. 

For efficient research, use an annotated code.  

Annotated codes are powerful research tools. They include:

  • statutory language
  • cross-references to other relevant statutes
  • regulations
  • leading cases
  • legislative documents, and
  • secondary sources that discuss the statute

*A note on positive law codification

Some titles of the U.S. Code have been enacted as positive law. This means that a whole code title has been restated and passed as a Federal Statute. A positive law title supersedes earlier enactments and serves as legal evidence of the text of a law. A non-positive law title is a compilation of laws from the Statutes at Large. It serves as "prima facie" evidence of the law, but can be rebutted by the text of the Statutes at Large. 

For more details and a current list of positive law titles and codification projects, see the Office of the Law Revision Counsel's web page. 

State Codes

States code are often also available in official or unofficial and annotated or unannotated versions.

Example. The Massachusetts Code is available in the following versions:

See Bluebook Table 1.3: States and the District of Columbia to identify code sources and citations for each state. 

Current State Codes

Current versions of state statutes are available online via Westlaw, Lexis, Bloomberg and state websites.

Current versions of state codes are also available in print in the Library reading room. See the section on Finding Statutes in the Library for tips on how to find them. 

Superseded State Codes

Historical and superseded statutes can be used to find out what the law was at a particular time in the past. 

Older state statutes are available online via Westlaw, Lexis and HeinOnline. Dates of coverage vary. Generally Lexis and Westlaw coverage of historical codes starts in the late 20th century. HeinOnline coverage generally includes the earliest versions of codes, but ends in the early -mid 20th century. 

Print and microfilm versions of superseded statutes are in storage. Use the table of HOLLIS & Hein Links to State Statutes linked below to locate and request them.

Find Codes in the Library

How to Find Statutes at HLSL

Note that Rule 12 of the 21st edition of the Bluebook allows citation to online codes.

Looking for a print or page image version of a U.S. federal  or state codes?

U.S. Code:

  • Print copies are located at call number KF62.
  • Page image copies are available via Heinonline

State Codes

  • Print copies of the current versions of some state statutes are located on the 4th floor of the Library in the reading room. Current state materials are shelved alphabetically by state starting at KFA. 
  • Print and microfilm copies of superseded state statutes are available. See the HOLLIS record for details
  • Some historic versions of state codes are available via Heinonline

See the  spreadsheet below for  HOLLIS and Heinonline versions of federal and state statutes.


See the video below for more details on how to submit a successful request. 

Requesting Scans of State Statutes for Cite Checking

Find Statutes by Citation or Name

Understanding Statutory Citations

Statutes are most easily located by a citation to public law number, session law number or code

U.S. Federal Laws:

See Bluebook Rule 12: Statutes


Dodd-Frank Wall Street Reform and Consumer Protection Act, Pub. L. No. 111-203, § 929-Z, 124 Stat. 1376, 1871 (2010) (codified at 15 U.S.C. § 78o) (emphasis added)

  • Slip law: Pub. L. No. 111-203, § 929-Z
    • Pub. L. No. indicates that this is a public law
    • 111 indicates the number of the Congress
    • 203 indicates that it is the 203rd law passed during that congress
    • § 929-Z is the specific section of the public law cited (the "pincite" or "pinpoint citation")
  • Session law: 124 Stat. 1376, 1871 (2010)
    • 124 is the volume number
    • Stat is the abbreviation for the Statutes at Large
    • 1376 is the first page where this law appears
    • 1871 is the pincite, indicating the page where the specific section cited appears
  • Code: 15 U.S.C. § 78o
    • 15 is the title/subject (Commerce and Trade)
    • U.S.C. is the abbreviation for the United States Code
    • § 78o is where the cited section was codified in the U.S. Code

U.S. State Laws:

State law citations vary by jurisdiction. For state code citation methods, consult the Bluebook,  Rule 12: Statutes and Table 1.3: States and the District of Columbia .

Finding a Statute by Citation in a Database

Databases may not recognize your citation format. These tools can help you format your citation and easily pull up a statutory section. 

Finding a Statute by Name: Popular Name Tables & Searching Online

Popular Name Tables

Statutes often have a common name such as the Dodd-Frank Act, Patriot Act or Family Medical Leave Act. You can find the statute using the name

Publishers create alphabetical tables of the popular names of statutes. The table contains session law citations and list of the sections where the law has been codified. The U.S. Code and many state statutory codes have popular name tables. 

Search Online

If you know the name of a law, you can also try searching online.  Major federal statutes may have a Wikipedia entry with citations and links. You may also find information about a statute in news sources, government websites and Library research guides. 

Classification Tables

If you have an incomplete citation or a citation that refers to a specific subsection of a session law,  and you want to find the relevant section of the code, try a classification table.  Statute classification tables list correspondences between the parts of recent session laws and the places in the code where they have been incorporated. 

Find Statutes by Subject

Getting Started without a Citation

Sometimes you will need to determine whether there is a controlling statute for a particular area of law. Before you start searching, identify the following:

  •  jurisdiction (federal, state or multiple jurisdictions)

  •  keywords (search terms that you will use to describe the legal question)

  •  time period (current law or law in force at some time in the past)

Remember: not all legal issues are governed by statute!

Secondary Sources

Secondary sources are usually the most efficient way to identify whether there is a controlling statute for your question and learn more about a particular area of the law.  For state law questions, look for a state legal encyclopedia, treatise or practice guide. Use earlier editions of treatises and practice guides to identify historical statutes. 

Subject Indexes

Use the subject index for the code in your jurisdiction. Indexes will usually be located in the print set, or online via Westlaw. Tips for index searching:

  • start with specific terms and proceed to more general terms
  • try synonyms and alternative expressions (e.g. "insolvency" and "bankruptcy")
  • be creative and persistent!

Go back to secondary sources if you fail to find an appropriate statute.

Keyword Searching

Statutory language is often very specialized, so keyword searching can be difficult.

Tips for keyword searching:

  • try to anticipate the language used by the legislature in writing the law
  • look at an encyclopedia or Wikipedia entry for particular legal topic to get key search terms
  • legal dictionaries, thesauri and other secondary sources can also help you develop search terms
  • Search an index (if available) to get synonyms for key terms - and citations to potentially relevant statutes.

50 State Surveys and Multi-Jurisdiction Comparisons

You may be asked to compare the law on a subject in multiple jurisdictions or create a 50 state survey of the law. This can be time consuming and tedious.  There are several tools and pre-compiled resources to help make this process easier. See our Research Guide to Comparing State Laws and Constitutions for details. 

Updating & Validating

Updating and Validating

Before relying on a statute, you need to be sure that it hasn't been amended, repealed or overturned by a court decision since it was published.

Updating Print Codes

To update a statute that you've found in print:

  • start in the main print volume
  • note the dates of coverage for the main volume
  • check for changes to your law in the pocket part in the back of the volume or the cumulative supplement
  • note the dates of coverage for the pocket part or supplement (these are usually published annually)
  • look in any recent legislative service pamphlets published after the supplements for
    • cumulative lists of statutes affected by recently enacted laws
    • cumulative subject index.
  • for U.S. Code sections, check the online classification tables for very recent changes

Other places to check:

  • check the history section of an online version of the code for any very recent changes
  • tables of amendments, repeals and new code provisions published in codes and advance legislative services 
  • check a citator like KeyCite or Shepard's for recent changes. 

Updating Online Codes

Check the currency note at the beginning of the code or code section when looking online. Most online versions of various codes are updated within 48 hours of legislative changes.

Next, look for any changes that might have occurred after the most recent update to the online statute. 

  • The U.S. Code Classification Tables are useful for identifying very recent additions and amendments to the U.S. Code.  These tables are sorted in U.S. Code order as well as by public law number.
  • Visit for recently enacted federal legislation to search for proposed additions or amendments to the U.S. Code. 
  • State legislative sites also offer bills in full text and commonly provide keyword searching and bill status information. 
  • Commercial databases such as Westlaw and Lexis provide state session law searching for state code updates.

Validating Codes

To establish the validity of a state law, use a citator like Shepard's, KeyCite or BCite to locate current cases and materials that analyze your statute.

  • Find and read the case law in your jurisdiction that cites your statute. 
  • Look out for court constitutionality rulings and other holdings affecting the statute's "good law" status.
  • Pay particular attention to signals indicating negative treatment by a court or legislative changes. 


Analyzing & Interpreting

Read & Browse

Read the statute carefully. Does it cover the legal issue you are researching?

Browse the Table of Contents or the chapter or title outline. What other sections seem relevant? 

Context is important when analyzing statutes.  In particular, look for:

  • purpose/legislative findings: These can help you understand why the legislature enacted the law.
  • definitions: Those definitions of words or phrases used in a law may vary from commonly accepted definitions.
  • exceptions: Exceptions to a general law are sometimes found in their own section

Review Annotations

Use statutory annotations to deepen your understanding of the statute and to continue your research for mandatory and persuasive case law precedent.

Annotations may include:

  • statutory history: When the statute was originally enacted and subsequently amended
  • analysis: Links and citations to selected helpful secondary sources such as treatises, ALRs,law reviews and other materials that focus on the statute
  • interpretation: References to important court decisions that have applied or interpreted the statute 

Check Citators

Citators like KeyCite (West) and Shepard's (Lexis) will lead you to cases that apply and interpret the statute and secondary sources that analyze and discuss the history and application of the statute.

Dig Deeper with Secondary Sources

Use secondary sources (treatises, practice guides, law review articles, etc.) to learn more about the context, history and analysis of a particular statute or area of law.

Secondary sources are also useful for exploring the methods and theory of statutory interpretation.

Trace the Legislative History

Legislative history is used for discovering sources of information about legislative intent.  Legislative history includes any of various materials generated in the course of creating legislation, such as reports, hearings and legislative debates. 

For more details, check out our HLSL guide to Federal Legislative History

Uniform Laws

Uniform Laws

You may see references to model or uniform laws.  These laws are usually developed by the Uniform Law Commission and are intended to bring "clarity and stability [in] critical areas of state statutory law."

These laws themselves are not binding, but many states have adopted them or incorporated parts of them into their codes.. A notable example is the Uniform Commercial Code.

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