About Libraries Online! Participating library systems in the United States include:
 
ALABAMA
Macon County-Tuskegee Public Library, Tuskegee
 
ARKANSAS
Central Arkansas Library System, Little Rock
 
ARIZONA
Phoenix Public Library
Tucson-Pima Public Library
 
CALIFORNIA
Los Angeles Public Library
Oakland Public Library
San Francisco Public Library
 
CONNECTICUT
Connecticut State Library, Middleton
Hartford Public Library
DISTRICT OF COLUMBIA
District of Columbia Public Library
FLORIDA
Miami-Dade Public Library
 
ILLINOIS
Chicago Public Library
 
MASSACHUSETTS
Boston Public Library
 
MARYLAND
Baltimore County Public Library, Towson
Wicomico County Free Library, Salisbury
 
MINNESOTA
Minneapolis Public Library
St. Paul Public Library
 
MISSOURI
Kansas City Public Library
St. Louis Public Library
 
MISSISSIPPI
Mississippi Library Commission, Jackson
Ada S. Fant Memorial Library, Macon
Bond Memorial Public Library, Ashland
Charleston Library, Charleston
Chocktaw County Public Library, Ackerman
Franklin County Public Library, Meadville
George W. Covington Memorial Library, Hazelhurst
Hariette Person Memorial Library, Port Gibson
Jefferson County Library, Fayette
Kevin Poole VanCleave Memorial Library, Centreville
Leaksville Public Library, Leaksville
Lexington Public Library, Lexington
Liberty Public Library, Liberty
Prentiss Public Library, Prentiss
Richton Public Library, Richton
Sharkey-Issaquena County Library, Rolling Fork
Vaiden Public Library, Vaiden
Walthall County Library, Tylertown
 
NORTH CAROLINA
Public Library of Charlotte & Mecklenburg County
 
NEBRASKA
Nebraska Library Commission, Lincoln
 
NEW JERSEY
Free Public Library of Elizabeth
NEW YORK
Brooklyn Public Library
Queens Borough Public Library
OKLAHOMA
Tsa-La-Gi Library, Cherokee Nation, Tahlequah
 
OREGON
Multnomah County Library, Portland
 
PENNSYLVANIA
Free Library of Philadelphia
Carnegie Library of Pittsburgh
York County Library System
 
SOUTH CAROLINA
Richland County Public Library, Columbia
 
SOUTH DAKOTA
South Dakota State Library, Pierre
Alexander Mitchell Public Library, Aberdeen
Bison Public School, Bison
Brookings Public Library, Brookings
Custer County Library, Custer
Deadwood Public Library, Deadwood
Emma Burnham Public Library, Frederick
Faith Community School Library, Faith
Grace Balloch Memorial Library, Spearfish
Haakon Community Library, Philip
Huron Public Library, Huron
Madison Public Library, Madison
McKay Building, Pierre
Mitchell Public Library, Mitchell
Ogala Lakota Community College, Kyle
Potter County Free Library, Gettysburg
Ralins Municipal Library, Pierre
Rapid City Public Library, Rapid City
Sturgis Public Library, Sturgis
Subte Geleska University Library, Mission
Vermillion Public Library, Vermillion
Watertown Regional Library, Watertown
White River School Library, White River
Yankton Community Library, Yankton
 
TENNESSEE
Memphis-Shelby County Public Library
 
TEXAS
San Antonio Public Library
 
UTAH
Utah State Library, Salt Lake City
Richfield Public Library, Richfield
Salina Public Library, Salina
Sevier, Wayne & Juab County Bookmoblile, Richfield
Toele City Public Library
 
WASHINGTON
King County Library System, Seattle
Niqually Tribal Library, Olympia
Pend Oreille County Library, Newport
Seattle Public Library
Timberland Regional Library, Olympia
Libraries Online! Canada
Libraries Online! Ireland