- Illustrated Blue Jay
- Independent Order of the Odd Fellows, Cochise Lodge
- Independent Order of the Odd Fellows, Comet Encampment
- Indian Claims Commission
- Inspiration Copper Co.
- International Brotherhood of Electrical Workers
- International Marble Company
- International Toastmistress Club
- Irwin, Bernard John Dowling
- Irwin, William E. diaries
- Isbell, Marion Papers
- Isbell, Marion Restaurants
- Iturbide, Joaquin de
- Ivancovich Family
- Ivancovich, Byron
- Ivancovich, Jane H.
- Ives, Eugene Semmes
- Ives, Ronald L
- Jaastad, Benjamin
- Jaastad, Henry
- Jackson, Mabel Ruth
- Jacobs Family
- Jacobs Family Business Records
- Jacobs, Barron
- Jacome, Katie H.
- James, George
- Jannette Kimble Pictorial Arizona Drawings
- Jaynes, Allan
- Jeffords, Thomas
- Jeffrey, John M.
- Johnson Family
- Johnson, Clarence
- Johnson, S. M.
- Johnston, Alexander
- Jones, Ada
- Jones, Melvin
- Jones, Morris Hunter
- Jones, Thomas
- Juarez, Ralph (Labor Union collection)
- Judd, Winnie Ruth (MS 1185)
- Judd, Winnie Ruth (MS 1203)
- Julian,William
- Junior League of Tucson
- Junior Woman’s Club
- Kantz, William
- Kearny, Stephen
- Keeling, Helen
- Kelly, Lon
- Kelly Family Papers
- Kemmeries, Fred
- Kennedy, Sylvia
- Kidder, Jefferson Parish
- Killip, Joyce
- King, Charles
- King, Peter
- Kingan, Samuel
- Kinney, Jack
- Kinsey, Luna
- Kirkland, Jacob
- Kirkland, William H.
- Kitchen, Pete
- Kite, Robert Edward Lee
- Kitt, Edith
- Kitt, George Roskruge
- Kiwanis Club
- Kiwanis Club of Tucson
- Kiwanis Scrapbook
- Kleinman Family
- Knaus, Charles L.
- Kneipp, Leon Frederick
- Knights of Pythias
- Knipe, Dorothy
- Krause, M. Warren
- KTAR Radio Scrapbooks
- KTAR Radio Scripts
- Kuykendall, Karen
- Kuzell, Charles R.
- La Osa Live Stock & Loan
- La Quintera Mining Company
- Lage, Patricia
- Laird, George
- LaMarr, John
- Langevin, Carmen May Browder
- Larsen, Orville and Fannie
- Larson, Leota
- Las Guijas Tungsten Mining Company
- Latham
- Laughlin, David
- Law Enforcement Collection
- Lawrence, Abbott
- Lawson, William
- Lawton, James M.
- Lea, Opie Rundle Burgess
- Leadville Townsite
- League of Women Voters of Greater Tucson
- League of Women Voters of Metropolitan Phoenix
- Leatherwood, Rufus. N.
- Lee Brothers
- Lee, John
- Lee, Russell
- Leonard, Herman and Ida
- Leonard, Ida
- Lescha Literary Society
- LeSueur, James Warren
- Levy, Leon
- Lewis, Ansel
- Lewis, Arthur
- Lewis Hall & Arizona Civil War Centennial
- Liggett, William
- Lindemann, Peter
- Lindsley, Stuart
- Literacy Connects
- Lockwood, Francis C.
- Lofgreen, Peter
- Lopez, Samuel
- Loring Family
- Loring, George
