List of largest libraries in the United States

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File:Thomas Jefferson Building Aerial by Carol M. Highsmith.jpg at the Library of Congress in Washington, D.C., the largest library in the United States and largest library in the world with over 167 million holdings, including 39 million books and other printed recordings, 14.8 million photographs, 5.5 million maps, 8.1 million pieces of sheet music, and 72 million manuscripts]]

The largest libraries in the United States is determined by the number of volumes or titles held, by circulation, including library materials checked out or renewed, or by number of library visits.The Nation's Largest Public Libraries: Home, American Library Association (last accessed December 24, 2018). As of 2018, the largest public library in the United States and largest library in the world is the Library of Congress in Washington, D.C., the de facto national library of the United States,James H. Billington, [https://www.britannica.com/topic/Library-of-Congress Library of Congress], Encyclopedia Britannica. which holds over 167 million items, including over 39 million books and other printed materials, 3.6 million recordings, 14.8 million photographs, 5.5 million maps, 8.1 million pieces of sheet music, and 72 million manuscripts.[https://www.loc.gov/about/fascinating-facts/ Fascinating Facts], Library of Congress (last accessed December 24, 2018). The largest research library in the United States, with nearly 20 million holdings, is the Harvard Library at Harvard University in Cambridge, Massachusetts.

Comparing the size of public libraries with research libraries, such as academic libraries, is complicated by the differing definitions of holdings or volumes used. The Association of Research Libraries uses the National Information Standards Organization definition of volume, which is, "A single physical unit of any printed, typewritten, handwritten, mimeographed, or processed work, distinguished from other units by a separate binding, encasement, portfolio, or other clear distinction, which has been cataloged, classified, and made ready for use, and which is typically the unit used to charge circulation transactions."The Nation's Largest Libraries: A Listing By Volumes Held (ALA Library Fact Sheet Number 22). American Library Association] (October 2012). The Public Library Data Service Statistical Report, a publication of the Public Library Association, a division of the American Library Association, defines "holdings" as "the number of cataloged items (number of items, number of titles) plus paperbacks and videocassettes even if uncataloged."

Largest public libraries systems by total collections

File:Public Building Library.jpg at New York Public Library in New York City, the nation's largest public library with over 25 million holdings]]

The American Library Association has published data on the size of 25 largest public libraries in the United States. These data are from the Institute of Museum and Library Services's Public Libraries Survey (PLS) for fiscal year 2016. The largest public libraries in the U.S. are far larger than the median public library in the country; almost four-fifths of U.S. public libraries serve areas with populations of fewer than 25,000.

"Total collection" consists of print material, electronic books, audio materials, and video materials, each of which is a particular "data element" defined in the PLS. Print materials include printed books, serial music, and maps, including duplicates; electronic books include digital documents include e-books and digitized documents, including duplicates; "audio materials" include both physical audio files (such as cassette tapes, audioreels, CD-ROMs, and talking books) and downloadable units; and "video materials" similarly includes both physical video materials (such as videotape and DVD) and downloadable video files.[https://www.imls.gov/sites/default/files/pls_defs_fy2016.pdf State Characteristics Data Element Definitions], Institute of Museum and Library Services (FY 2016).

class="wikitable"
RankLibraryArea servedTotal collection (FY 2016)
1New York Public LibraryManhattan, The Bronx, and Staten Island, New York City, NY25,271,223
2Cincinnati and Hamilton County Public LibraryHamilton County, OH11,721,430
3Mid-Continent Public LibraryJackson County, Clay County, and Platte County, MO8,970,728
4Boston Public LibraryBoston, MA8,197,010
5Los Angeles Public LibraryLos Angeles, CA6,735,561
6Chicago Public LibraryChicago, IL5,949,251
7County of Los Angeles Public LibraryLos Angeles County, CA5,779,843
8Queens Borough Public LibraryQueens, New York City, NY5,670,563
9San Diego Public LibrarySan Diego, CA5,272,779
10Dallas Public LibraryDallas, TX5,155,647
11Hennepin County LibraryHennepin County, MN4,895,312
12Dayton Metro LibraryDayton, OH4,719,674
13Detroit Public LibraryDetroit, MI4,394,193
14King County Library SystemKing County, WA3,967,872
15Cleveland Public LibraryCleveland, OH3,946,416
16Cuyahoga County Public LibraryCuyahoga County, OH3,661,264
17Brooklyn Public LibraryBrooklyn, New York City, NY3,660,532
18Miami-Dade Public Library SystemMiami-Dade County, FL3,626,153
19Allen County Public LibraryAllen County, IN2,450,882
20Hawaii State Public Library SystemHawaii3,403,577
21City of St. Louis Municipal Library DistrictSt. Louis, MO3,281,380
22Broward County Libraries DivisionBroward County, FL3,194,345
23San Francisco Public LibrarySan Francisco, CA3,122,259
24Houston Public LibraryHouston, TX3,084,633
25Las Vegas-Clark County Library DistrictClark County, NV3,041,019

Largest research libraries

File:Boston, Massachusetts (50912673886).jpg, part of the Harvard Library at Harvard University]]

The Association of Research Libraries (ARL), a consortium of U.S. and Canada research libraries, reports statistical data on its 124 members (of which 114 are academic libraries within universities and 10 are non-academic research libraries). The ten non-university institutions in the ARL are the Boston Public Library, National Research Council Canada National Science Library, Center for Research Libraries, Library of Congress, National Agricultural Library, National Archives, National Library of Medicine, New York Public Library, New York State Library, and Smithsonian Libraries.

The following volume figures for the largest 20 U.S. and Canada research libraries by volume were reported in ARL Statistics, 2020, published in 2022. Some ARL member libraries include the holdings of law libraries, medical libraries, and branch campuses in their reported statistics; others do not.{{Cite book |last=Mian |first=Anam |url=https://publications.arl.org/ARL-Statistics-2020/ |title=ARL Statistics 2020 |last2=Roebuck |first2=Gary |publisher=Association of Research Libraries |year=2020 |location=Washington, DC |pages=}}

=25 largest research libraries by volumes held=

The following are the 25 ARL members with the largest number of volumes held. ARL uses the ANSI/NISO Z39.7-2004 definition of "volume": "a single physical unit of any printed, typewritten, handwritten, mimeographed, or processed work, distinguished from other units by a separate binding, encasement, portfolio, or other clear distinction, which has been catalogued, classified, and made ready for use."Morris & Roebuck (2018), p. 61. Microform, maps, and "electronic serials and other virtual serial volumes" are excluded from the volume count.

class="wikitable"
RankLibraryInstitution

!Type|| Volumes (2020){{Rp|45}}

1Harvard LibraryHarvard University

|Private

19,608,349
2

|University of Michigan Library

|University of Michigan

|Public

|16,025,996

3Yale University LibraryYale University

|Private

15,421,200
4University of Illinois Urbana-Champaign University LibraryUniversity of Illinois Urbana-Champaign

|Public

15,385,227
5Columbia University LibrariesColumbia University

|Private

15,029,945{{Refn|Columbia University Libraries is closely affiliated with the Jewish Theological Seminary Library, whose collection consists of over 400,000 volumes, but in not included in the ARL count.|name=fn1|group=a}}
6University of California, Berkeley LibrariesUniversity of California, Berkeley

|Public

13,890,919 [https://libraries.universityofcalifornia.edu/wp-content/uploads/2022/12/Library_Statistics_21-22_v3.pdf]
7

|University of Chicago Library

|University of Chicago

|Private

|12,458,055

8

|University of Wisconsin–Madison

|University of Wisconsin System

|Public

|11,995,591

9University of California, Los Angeles LibraryUniversity of California, Los Angeles

|Public

11,421,038

[https://libraries.universityofcalifornia.edu/wp-content/uploads/2022/12/Library_Statistics_21-22_v3.pdf]

10Indiana University LibrariesIndiana University

|Public

11,260,449
11Princeton University LibraryPrinceton University

|Private

10,510,491
12University of Texas LibrariesUniversity of Texas at Austin

|Public

10,102,977
13Cornell University LibraryCornell University

|Private

10,075,313
14

|Ohio State University Libraries

|Ohio State University

|Public

|9,842,514

15University of Iowa LibrariesUniversity of Iowa

|Public

9,827,159
16University of Washington LibrariesUniversity of Washington

|Public

9,772,809
17UNC Chapel Hill LibrariesUniversity of North Carolina at Chapel Hill

|Public

9,555,566
18Pennsylvania State University LibrariesPennsylvania State University

|Public

9,481,893
19Duke University LibrariesDuke University

|Private

9,046,010
20

|New York University Libraries

|New York University

|Private

|8,935,822

21Penn LibrariesUniversity of Pennsylvania

|Private

8,880,872
22Northwestern University LibraryNorthwestern University

|Private

8,449,608
23

|University of Colorado Boulder University Libraries

|University of Colorado Boulder

|Public

|8,337,273

24

|Oklahoma State University Libraries

|Oklahoma State University System

|Public

|8,012,463

25Michigan State University LibrariesMichigan State University

|Public

7,898,847

=25 largest research libraries by titles held=

The following are the 25 ARL members with the largest number of titles held, "including catalogued, locally digitized, and licensed" titles.Morris & Roebuck (2018), p. 60. ARL follows the ANSI/NISO Z39.7-2004 definition of "title": "The designation of a separate bibliographic whole, whether issued in one or several volumes...Titles are defined according to the Anglo-American Cataloging Rules. A book or serial title may be distinguished from other titles by its unique International Standard Book Number (ISBN) or International Standard Serial Number (ISSN)." Multiple copies of the same work (for example, subscriptions to the same publication) are counted as a single title, but a serial title available in multiple formats (for example, print and online) are counted once for each available format.

class="wikitable"
RankLibraryInstitution || Titles Held (2020){{Rp|46}}
1Harvard LibraryHarvard University18,711,275
2University of California, Los Angeles LibraryUniversity of California, Los Angeles17,679,327
3Yale University LibraryYale University12,826,347
4

|Columbia University Libraries

|Columbia University

|10,814,827{{Refn|Columbia University Libraries is closely affiliated with the Jewish Theological Seminary Library, whose collection consists of over 400,000 volumes, but in not included in the ARL count.|name=fn1|group=a}}

5

|University of Michigan Library

|University of Michigan

|10,692,811

6University of California, Berkeley LibrariesUniversity of California, Berkeley9,816,654
7University of Illinois Urbana-Champaign University LibraryUniversity of Illinois Urbana-Champaign9,546,739
8University of Wisconsin–Madison LibraryUniversity of Wisconsin9,211,820
9Princeton University LibraryPrinceton University9,163,538
10Indiana University LibrariesIndiana University8,995,411
11Michigan State University LibrariesMichigan State University8,855,996
12New York University LibrariesNew York University8,544,313
13Cornell University LibraryCornell University8,364,927
14Northwestern University LibraryNorthwestern University8,198,268
15Pennsylvania State University LibrariesPennsylvania State University8,191,408
16University of Texas LibrariesUniversity of Texas at Austin8,152,478
17University of Chicago LibraryUniversity of Chicago8,151,994
18Penn LibrariesUniversity of Pennsylvania7,464,058
20

|University of Colorado Boulder University Libraries

|University of Colorado Boulder

|7,086,420

21

|Duke University Libraries

|Duke University

|7,037,558

22Ohio State University LibrariesOhio State University6,855,146
23

|University of Virginia Library

|University of Virginia

|6,854,203

24

|University of Washington Libraries

|University of Washington

|6,831,932

25

|Louisiana State University Libraries

|Louisiana State University

|6,457,134

See also

Footnotes

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