You can start here at the Reference and Users Services Association for information on Using Primary Sources on the Web
- A good primary source site for history. The digital collections include photos, books newspapers and more. Includes American History and World History sources.
National Union Catalog of Manuscript Collections (Library of Congress)
OEDb 250+ Killer Digital Libraries and Archives (Open Education Database) Contains state by state links to digital sources.
Mexican/Mexican American/Latin American History
Aztec Club - database search - most complete record of Mexican War service by American officers
Digital Archive of the Guatemalan National Police Historical Archive (The University of Texas at Austin)
Military Resources: Mexican War, 1846-1848 Archives Library Information Center (ALIC) (National Archives)
Historic Mexican and Mexican American Press The University of Arizona's Border Newspapers Archive
California - The Brancroft Library, University of California History Digital Archives
Eastern New Mexico University - Oral Histories - from Roosevelt County and Easter New Mexico
New Mexico's Digital Collections, Palace of the Governors - The New Mexico History Museum
UTSA Digital Collections (The University of Texas at San Antonio)
UNT Digital Collections (University of North Texas Libraries)