Superintendent of Documents Classification: Government Information Research Guide

How to Find a Government Publication at the NCSU Libraries

(or, What's a SuDoc?)


Government Documents Collection Organization

Location: Hunt Library bookBot
Organization: Superintendent of Documents (SuDoc) classification system

The guiding principle of SuDoc classification is organization that reflects the organization of the U.S. government. This necessarily means that the organization of materials changes over time as government agencies change.

The format of a SuDoc number is as follows:

Department [Letter(s)] Agency # Series #

For example: NAS 1.26 indicates a NASA series, Contractor Reports. Or, I is for the Department of the Interior, 19 is for the U.S. Geological Survey and 42 is the number of the USGS series, Water Resources Investigations Report.

example SuDocs

Whereas the second number in a Library of Congress (LC) call number is shelved as a decimal number, the series number in SuDoc classification is shelved as a whole number, despite following a decimal point.

Example of correct shelving order by series numer:

HE 20.39:
HE 20.102:
HE 20.310:
HE 20.3092:

In the NASA example, this "class stem" would be followed by another number, the specific report's number as assigned by the agency.


To Find a Specific Item

For help identifying the appropriate SuDoc for a given publication, you may:

  • Check our catalog if it was published after 1998 (partly to see if we own it). We began adding electronic records to the online catalog in that year but we also own much older material that **is not** in the online catalog. Remember to search for any series titles if an exact title search doesn't work.
  • Check the Government Printing Office's Catalog of U.S. Government Publications if it was published after 1976.
  • Look up a series title in the Guide to U.S. Government Publications, commonly known as Andriot (the editor's name). The current edition is located in the Reference section in the Learning Commons, with an LC call number, Z1223.Z7 G8. It enables look up by title, title keyword and agency, and provides brief historical notes on agency formation and change over time.
  • Check the WorldCat database for your title to see if any libraries nationally have noted its SuDoc number. (Our SuDoc may be slightly different but this may get you close.)
  • See our strategies by publication date for more suggestions. Remember, the date your item was published can make a difference in its SuDoc number. It can also make a difference in where you can find a record for it.
  • Contact a reference librarian.


More Explanation


The first letter of a SuDoc number refers to the parent department of the agency which publishes the document. For example:

A - Agriculture
C - Commerce

Successive agencies are designated based on which letters are already in use:

N - Navy (formed 1798)
NA - National Acadamies (formed 1863)
NAS - NASA (formed 1958)

Department letter designations are generally related to the name of the agency except Congress which uses the letters X and Y.

Agency or Office

The number which follows the letter(s) designates subordinate agencies, with the number 1 referring to the parent department and the secretary's or administrator's office. Starting with 2, numbers were assigned to existing agencies and offices when the SuDoc system was created in the early twentieth century. Any added later were assigned the next highest number.

T 1 - Department of the Treasury
T 2 - Appointments Division
T 12 - Comptroller of the Currency
T 17 - Customs Service

The Customs Service was transferred to the Department of Homeland Security in 2003. Where would one find it's post-2003 publications? In HS 4. Likewise, the Census Bureau was originally established in the Department of the Interior, so publications from 1790 to 1903 are found in I.

As a government agency changes, its SuDoc changes.

Some agencies have no major subordinate agencies or offices and consequently only use the number 1. NASA is one of these.


Agency numbers in the SuDoc system are followed by a decimal point. Numbers after the decimal point refer to different kinds of publications. The following series designations are common across different agencies:

1 - Annual reports
2 - General publications (unnumbered publications of a miscellaneous nature)
3 - Bulletins
4 - Circulars
5 - Laws (administered by the agency and published by it)
6 - Regulations, rules, and instruction
7 - Releases
8 - Handbooks, manuals, guides
9 - Bibliographies and lists of publications
10 - Directories
11- Maps and charts
12 - Posters
13 - Forms
14 - Addresses, lectures, etc.

An agency can also, of course, develop its own unique series. Such a series is assigned the next highest available number. NASA, for instance, assigns the number 26 for its Contractor Reports.

Whereas the second number in a Library of Congress (LC) call number is read as a decimal number, the series number in SuDoc classification is read as a whole number.

Example of correct shelving order by series numer:

HE 20.39:
HE 20.102:
HE 20.310:
HE 20.3162:


Why Use SuDocs?

We (and most federal depository libraries) use SuDoc classification to organize these collections because it is more efficient. It's quicker to use numbers that the Government Printing Office supplies along with the publications than it is to send the federal depository material through the technical services processes within the library. It would also be hugely expensive to convert the existing collection to Library of Congress classification.


If you entered through the Federal Government Documents Tutorial, continue here:

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