Book and Film Numbers Used by the Family History LibraryEdit This Page

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Family History Library



The Family History Library has used a few different methods to number its books and films since the library started in 1894. These old numbers for books and films are no longer used so the current numbers for the books and films must be determined.

There have been two systems for numbering books and three systems for numbering films.

Book Numbers

1. Previous book numbering system

The first numbering system for books used a topic code or a geographic code and a number, such as:

  • R8A21 (reference books began with an 'R')
  • NY 134 (a book about New York)
  • Eng 369 (a book about England)

The numbers were assigned in the order the book was received into the library's collection.

Family histories were grouped into classes 'A' or 'B', such as:

  • A5D8
  • B15A139

There was no direct corrolation between any of the letters in the call number and the surname of the family whom the book was about. 

2. Current book numbering system

The current book numbering system is based on the universally recognized Dewey Decimal system, with only slight alterations. The Dewey Decimal system designator for histories is the 900 series. Since the majority of the library's books are historical in nature, the 900 series is used most in the library. Other designators seen in the library are:

  • 000 series for general works (such as 030 for encyclopedias and 040 for biographies)
  • 200 series for religion
  • 400 series for language (including dictionaries)

The 940 series is for European histories. These include:

  • 941 British Isles (in the Family History Library this is for Scotland and 941.5 for Ireland)
  • 942 England & Wales in particular
  • 943 Central Europe; Germany
  • 944 France & Monaco
  • 945 Italian Peninsula & adjacent islands
  • 946 Iberian Peninsula & adjacent islands
  • 947 Eastern Europe; Russia
  • 948 Northern Europe; Scandinavia

For the United States and Canada, these are the designators:

  • 970 General history of North America
  • 971 Canada
  • 972 Middle America; Mexico
  • 973 United States
  • 974 Northeastern United States
  • 975 Southeastern United States
  • 976 South central United States
  • 977 North central United States
  • 978 Western United States
  • 979 Great Basin & Pacific Slope

All of these designators are used in the Family History Library with slight additions and variations. Within a region, such as 974 for Northeastern United States, an added period (.) and additional number designates a state within that region, such as 974.7 for New York state.  Additional numbers after the .7 further narrow the designation to a county within the state. Another example would be 942.1 for the county of Middlesex in England.

The numbers may be followed by a slash and a letter and number, such as /A1. This last part indicates a city or town within a county. An example would be 942.1/L1 = London, Middlesex, England.

The remaining part of a book number indicates the subject of the book and the name of the author such as:

  • H2ab for a history by Benjamin Allen
  • X22b for a census index created by the Bedfordshire Family History Society

Microfilm Numbers

Microfilm numbers are also referred to as "GS Numbers" referring to The Genealogical Society of Utah.

1. First numbering System

The first numbering system for films used an F (for film), then F.H. (for family history) or a geographic code, then a number or a letter and number and often a part number. A part number designated a separate film in a film series. Examples:

  • F F.H. 441
  • F Ga. 7
  • F Me. 11 pt. 289
  • F Pa. C 9f pt. 1
  • F Mass. H3
  • F N.Y. C 16b
  • F Vt. W 25a pt. 2

2. Second numbering system

The second numbering system was just numbers, starting at number 1, often with a part number attached. These numbers were also called "red numbers" because, for a number of years, the numbers were printed in red ink on the film boxes. Again a part number designated a separate film in a series of films. Examples:

  • 1448
  • 2756 pt. 356
  • 7079 pt. 2
  • 2745
  • 14505 pt. 1059

The tricky part of this system is how to know if a number without a part number -- such as 2745 -- is an old, red number or if it is a current number. Old, red numbers stopped at about 60,000, so any past that are current numbers.

3. Third numbering system

The current numbering system started over with number 1 and new films are assigned the next sequential number. No letters or part numbers are used. As the library now has over 2 million films in its collection, zeros are sometimes added on the front of a film number to make it a 7-digit number, but they are not needed. Numbers are good with or without the leading zeros. For example:

  • 0000001
  • 4821
  • 20589
  • 490682
  • 2087254

Blocks of numbers were assigned to regions and by film size (16 and 35 mm). Because of this you will find that sequential numbers may be from the same country but not from the same project.

Digital Filming Numbers

When the Genealogical Society of Utah began acquiring records digitally these images were assigned numbers in the 4,000,000 range. In 2014 new digital acquisitions were assigned numbers in 10,000,000 range. These are generally referred to as "DGS" numbers.

As existing microfilms were scanned they were assigned numbers in the 4,000,000 range and later in the 7,000,000 range..

Converting Old Film Numbers to New

Here are several ways to convert the old GS film numbers into the current Family History Library film numbers.

If you need to convert an old GS book number, consult one of these resources, most of which are available on film or fiche.

See Also


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  • This page was last modified on 4 February 2016, at 19:41.
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