Anatomy of a Library of Congress Call Number

Library of Congress (LOC) Call Numbers (sometimes referred to as Call Letters), are a series of alphabetical and numerical characters that are placed on the spines (or other suitable locations) of library materials to denote where each one belongs on the shelf.

LOC call numbers are a little bit more complex than call numbers in the Dewey Decimal system, but LOC allows for more precise sorting.

A LOC call number might look something like this:


The first letter or letters + the first set of numbers in a LOC call number are an item's Class and Subclass.  These are used to group materials that contain information on the same, or similar, topics.

The second (and sometimes third, fourth, etc.) set of characters -- which start with a decimal point -- are called "Cutter Numbers".  These help librarians sort items based on author, geographic region, or a number of other relevant pieces of metadata depending on the item.  The LOC classification system calls for different types of cutter numbers in different circumstances.

The last set of numbers (if present) denotes the publication year.

Finally, items that: the library has multiple copies of, are one in a series, are part of a special collection, or that are a unique type of media among others in their shelving location, might have additional lines in their LOC call number either at the top or the bottom to communicate these circumstances.  Examples: "REF" - item is a part of the reference collection; "Copy 2" - library owns multiple copies; "Vol. 29 - item is one of a series of volumes; "DVD" - item is, well, a DVD.


Class A - General Works

Subclass Identifiers

AC Collections.  Series.  Collected works.
AE Encyclopedias.
AG Dictionaries and other general reference works.
AI Indexes.
AM Museums.
AN Newspapers.
AP Periodicals.
AS Academies and learned societies.
AY Yearbooks.  Almanacs.  Directories.
AZ History of scholarship and learning.  The humanities.


Class B - Philosophy, Psychology, Religion

Subclass Identifiers
B Philosophy (General).
BC Logic.
BD Speculative philosophy.
BF Psychology.
BH Aesthetics.
BJ Ethics.
BL Religions.  Mythology.  Rationalism.
BM Judaism.
BP Islam.  Bahaism.  Theosophy, etc.
BQ Buddhism.
BR Christianity.
BS The Bible.
BT Doctrinal Theology.
BV Practical Theology.
BX Christian Denominations.

Class B - Auxiliary Sciences of History

Subclass Identifiers
C Auxiliary Sciences of History (General).
CB History of Civilization.
CC Archaeology.
CD Diplomatics.  Archives.  Seals.
CE Technical Chronology.  Calendar.
CJ Numismatics.
CN Inscriptions.  Epigraphy.
CR Heraldry.
CS Geneaology.
CT Biography.


Class D - World History and History of Europe, Asia, Africa, Australia, New Zealand, Etc.

Subclass Identifiers
D History (General).
DA Great Britain.
DAW Central Europe.
DB Austria - Liechtenstein - Hungary - Czechoslovakia.
DC France - Andorra - Monaco.
DD Germany.
DE Greco-Roman World.
DF Greece.
DG Italy - Malta.
DH Low Countries - Benelux Countries.
DJ Netherlands (Holland).
DJK Eastern Europe (General).
DK Russia.  Soviet Union.  Former Soviet Republics - Poland.
DL Northern Europe.  Scandinavia.
DP Spain - Portugal.
DQ Switzerland.
DR Balkan Peninsula.
DS Asia.
DT Africa.
DU Oceania (South Seas).
DX Romanies.

Class E - History of the Americas

Class F - History of the Americas

Subclass Identifiers
F1-975 United States local history.
F1001-1145.2 British America (including Canada).  Dutch America.
F1170 French America.
F1201-3799 Latin America.  Spanish America.


Class G - Geography, Anthropology, Recreation

Subclass Identifiers
G Geography (General).  Atlases.  Maps.
GA Mathematical geography.  Cartography.
GB Physical geography.
GC Oceanography.
GE Environmental Sciences.
GF Human ecology.  Anthropogeography.
GN Anthropology.
GR Folklore.
GT Manners and customs (General).
GV Recreation.  Leisure.

Class H - Social Sciences

Subclass Identifiers
H Social sciences (General).
HA Statistics.
HB Economic theory.  Demography.
HC Economic history and conditions.
HD Industries.  Land use.  Labor.
HE Transportation and communications.
HF Commerce.
HG Finance.
HJ Public finance.
HM Sociology (General).
HN Social history and conditions.  Social problems.  Social reform.
HQ The family.  Marriage.  Women.
HS Societies: secret, benevolent, etc.
HT Communities.  Classes.  Races.
HV Social pathology.  Social and public welfare.  Criminology.
HX Socialism.  Communism.  Anarchism.

Class J - Political Science

Subclass Identifiers
J General legislative and executive papers.
JA Political science (General).
JC Political theory.
JF Political institutions and public administration.
JJ Political institutions and public administration (North America).
JK Political institutions and public administration (United States).
JL Political institutions and public administration (Canada, Latin America, etc.).
JN Political institutions and public administration (Europe).
JQ Political institutions and public administration (Asia, Africa, Australia, Pacifica Area, etc.).
JS Local government.  Municipal government.
JV Colonies and colonization.  Emigration and immigration.  International migration.
JX (obsolete) International law, see JZ and KZ.
JZ International relations.


Class K - Law

Subclass Identifiers
K Law in general.  Comparative and uniform law.  Jurisprudence.
KB Religious law in general.  Comparative religious law.  Jurisprudence.
KBM Jewish law.
KBP Islamic law.
KBR History of canon law.
KBU Law of the Roman Catholic Church. The Holy See.
KD-KDK United Kingdom and Ireland.
KDZ America.  North America.
KE Canada.
KF United States.
KG Latin America - Mexico and Central America - West Indies.  Caribbean area.
KH South America.
KJ-KKZ Europe.
KL-KWX Asia and Eurasia, Africa, Pacific Area, and Antarctica.
KZ Law of Nations.

Class L - Education

Subclass Identifiers
L Education (General).
LA History of education.
LB Theory and practice of education.
LC Special aspects of education.
LD Individual institutions - United States.
LE Individual institutions - America (except United States).
LF Individual institutions - Europe.
LG Individual institutions - Asia, Africa, Indian Ocean islands, Australia, New Zealand, Pacific islands.
LH College and school magazines and papers.
LJ Student fraternities and societies, United States.
LT Textbooks.

Class M - Music and Books on Music

Subclass Identifiers
M Music.
ML Literature on music.
MT Instruction and study.


Class N - Fine Arts

Subclass Identifiers
N Visual arts.
NA Architecture.
NB Sculpture.
NC Drawing.  Design.  Illustration.
ND Painting.
NE Print media.
NK Decorative arts.
NX Arts in general.

Class P - Language and Literature

Subclass Identifiers
P Philology.  Linguistics.
PA Greek language and literature.  Latin language and literature.
PB Modern languages.  Celtic languages.
PC Romance languages.
PD Germanic languages.  Scandinavian languages.
PE English language.
PF West Germanic languages.
PG Slavic languages.  Baltic languages.  Albanian language.
PH Uralic languages.  Basque language.
PJ Oriental languages and literatures.
PK Indo-Iranian languages and literatures.
PL Languages and literatures of Eastern Asia, Africa, Oceania.
PM Hyperborean, Indian, and artificial languages.
PN Literature (General).
PQ French literature - Italian literature - Spanish literature - Portuguese literature.
PR English literature.
PS American literature.
PT German literature - Dutch literature - Flemish literature since 1830 - Afrikaans literature - Scandinavian literature - Old Norse literature: Old Icelandic and Old Norwegian - Modern Icelandic literature - Faroese literature - Danish literature - Norwegian literature - Swedish literature.
PZ Fiction and juvenile belles lettres.

Class Q - Science

Subclass Identifiers
Q Science (General).
QA Mathematics.
QB Astronomy.
QC Physics.
QD Chemistry.
QE Geology.
QH Natural history - Biology.
QK Botany.
QL Zoology.
QM Human anatomy.
QP Physiology.
QR Microbiology.


Class R - Medicine

Subclass Identifiers
R Medicine (General).
RA Public aspects of medicine.
RB Pathology.
RC Internal medicine.
RD Surgery.
RE Ophthalmology.
RF Otorhinolaryngology.
RG Gynecology and obstetrics.
RJ Pediatrics.
RK Dentistry.
RL Dermatology.
RM Therapeutics.  Pharmacology.
RS Pharmacy and materia medica.
RT Nursing.
RV Botanic, Thomsonian, and eclectic medicine.
RX Homeopathy.
RZ Other systems of medicine.

Class S - Agriculture

Subclass Identifiers
S Agriculture (General).
SB Plant culture.
SD Forestry.
SF Animal culture.
SH Aquaculture.  Fisheries.  Angling.
SK Hunting sports.

Class T - Technology

Subclass Identifiers
T Technology (General).
TA Engineering (General).  Civil engineering.
TC Hydraulic engineering. Ocean engineering.
TD Environmental technology.  Sanitary engineering.
TE Highway engineering.  Roads and pavements.
TF Railroad engineering and operation.
TG Bridge engineering.
TH Building construction.
TJ Mechanical engineering and machinery.
TK Electical engineering.  Electronics.  Nuclear engineering.
TL Motor vehicles.  Aeronautics.  Astronautics.
TN Mining engineering.  Metallurgy.
TP Chemical technology.
TR Photography.
TS Manufactures.
TT Handicrafts.  Arts and crafts.
TX Home economics.


Class U - Military Science

Subclass Identifiers
U Military science (General).
UA Armies: Organization, distribution, military situation.
UB Military administration.
UC Maintenance and transportation.
UD Infantry.
UE Cavalry.  Armor.
UF Artillery.
UG Military engineering.  Air forces.
UH Other services.

Class V - Naval Science

Subclass Identifiers
V Naval science (General).
VA Navies: Organization, distribution, naval situation.
VB Naval administration.
VC Naval maintenance.
VD Naval seamen.
VE Marines.
VF Naval ordnance.
VG Minor services of navies.
VK Navigation.  Merchant marine.
VM Naval architecture.  Shipbuilding.  Marine engineering.

Class Z - Bibliography, Library Science, Information Resources (General)

Subclass Identifiers
Z Books (General).  Writing.  Paleography.  Book industries and trade.  Libraries.  Bibliography.
ZA Information resources (General).