- Cababi Consolidated Mining Company
- Cabat-Gill Advertising Agency
- Caldwallader, S.
- Caldwell, Mary E.
- Caldwell, William H.
- California Justice Court
- Callaghan, John C.
- Calvillo, Ignacio
- Cameron, James D.
- Cameron, Ralph
- Camp Brodie
- Camp Fire Girls, Southern Arizona Council
- Campbell Family
- Campbell, John Henry
- Campbell, John Henry (Baca Float No. 3)
- Campbell, John Henry (Cattle Co.)
- Canal Companies of Arizona
- Cananea Consolidated Copper Company
- Cananea Mining
- Cannon, Jennie V.
- Cargill, Andrew H.
- Carleton, James
- Carman Consolidated Copper Company
- Carroll, Elva H.
- Carroll, F. L. J.
- Carroll, John A.
- Casanega, Thomas
- Cason, Mabel E.
- Cassidy, Michael E.
- Castaneda, A. A.
- Castillo, Jose del
- Cattle Brand Collection
- Central Arizona Telegraph Co.
- Central Copper Company
- Century House
- Certificate Collection
- Chaffee, Adna R.
- Chafin, Carl Research Collection
- Chambers, Ethel
- Chambers, George W.
- Chamizal Title Company
- Charleston Mines
- Charouleau, Anna
- Chase, Alexander
- Chattman, Thomas B.
- Cheetham, Francis
- Chicago Title Company
- Childs, Eugene
- Chillson, L. D.
- Cholla Business & Professional Women’s Club
- Chrisman, Clarence
- Christensen, Christian Lingo
- Citizens Protective League
- City of Tucson Property Records
- Civilian Conservation Corps newsletters
- Clark, Charles
- Clark, E. P.
- Clark, John A.
- Clark, Julian
- Clark, Vernon
- Clarke, Phil M.
- Clayton, Wallace
- Clum, John P.
- Cochise County Newspaper Survey
- Cochise County Records
- Cochran, Orville
- Coconino Caverns
- Codices and Facsimiles collection
- Coggin, H. Mason Mining Collection
- Cohen, Morris
- Coleman, Evans
- Coleman, Jane Candia
- Collingwood, Joseph D. & Elena Barrágan
- Collins, Thomas
- Colossal Cave Visitors Register
- Common Council of the Village of Tucson Arizona
- Commonwealth Mining & Milling Company
- Comstock Children’s Hospital & Foundation
- Confer, Lawrence W.
- Connell, Charles
- Connor, Daniel
- Control Mine Company
- Contzen Family
- Cook, Charles H.
- Cook, Earle
- Cooley, Corydon
- Copper Bell Mining Company
- Corbett Family
- Cordero, Antonio
- Cordis, Thomas
- Corona Ranch Tucson
- Corridos Mexicanos
- Cosulich, Bernice
- Coues, Elliot
- Couts, Cave Johnson
- Cowden, E. Ray
- Cox, Annie
- Cox, Joseph M.
- Coyne, Patrick
- Coyote Journal
- Craig, Geraldine
- Crampton, John
- Crawford, S. W.
- Creighton, James M.
- Croix, Cabellero Teodoro de (English)
- Croix, Teodoro de (Español)
- Cronly, Andrew
- Crook, George
- Cross, Walter & Ewing
- Cruse, Thomas
- C. S. Shotwell & Company
- Culin, Beppie L.
- Cummings, Byron Typescripts
- Curlee, Arthur
- Curnow, Alice
