Historical Image Sources

The photographs, illustrations, and historical images used on this site come primarily from public domain archives in the United States and Mexico.

Many of these materials are more than a century old and are no longer protected by copyright. We sometimes make minor edits to improve readability for digital use, such as adjusting brightness, contrast, or cropping. The underlying historical image remains in the public domain.

Whenever possible, we include the original source so that readers can locate the image in the archive where it is preserved.

Archives and Collections

Images on this site may come from digital collections such as:

United States archives

• Library of Congress
• U.S. National Archives
• New York Public Library Digital Collections
• Smithsonian Institution collections

Mexican archives and libraries

• Biblioteca Nacional de México
• Hemeroteca Nacional Digital de México
• Archivo General de la Nación (México)
• Biblioteca Digital Mexicana
• Archivo General del Estado (various states)

These institutions digitize and share historical materials so researchers, educators, and the public can access them.

How to Attribute Images

Even when an image is in the public domain, it is good historical practice to credit the archive that preserves it.

If you use an image from this site, please include the following information whenever possible:

Basic attribution format

Title or description of image
Name of archive or collection

Example

Saltillo Cathedral, ca. 1880
Library of Congress Prints and Photographs Division

Why Attribution Matters

Historical images survive because archives preserve them and make them accessible to the public. Crediting the archive helps others locate the original materials and supports responsible research.