Series 1. consists of photographic prints and negatives created or collected by Herrera. The bulk of the photographs taken by Herrera date from approximately 1960 to 1980, documenting a range of subjects and locations. A significant portion of this series is devoted to Herrera's Three Crosses series, represented across multiple boxes and folders (Box 12g; Box 15c–15d; Box 24e; Box 27d; Box 28a–28b, 28e; and Box 10, Folder 2). In addition to the Three Crosses series, the series includes photographs of various geographic locations. Within West Virginia, documented sites include Monrovia, Parkersburg, Cripple Creek, and Sugar Grove. The series further encompasses images from other regions in the United States, such as Wyoming and Maryland, as well as international locations including Spain and Canada.

Series 2. This series contains assorted newspaper clippings, correspondence, and related documentary materials pertaining to Herrera's careers as both a professor and a photographer. The newspaper clippings include reviews, feature articles, exhibition announcements, and press coverage that document Herrera's professional achievements, public reception, and involvement in academic and artistic communities. 

Series 3 consists primarily of oversized photographic prints created by Herrera, along with two boxes (Box 36, Folder 2; and Box 40) containing photographic prints collected by Herrera. Most of the materials in this series date from approximately 1970 to 1989. The oversized prints by Herrera reflect his photographic work across a range of locations and subjects. Geographic coverage includes West Virginia, Maryland, and Colorado, among other areas. Box 40 contains assorted black-and-white photographic prints, many of which were incorporated into gallery exhibitions and display installations. These prints represent locations such as Scotland, Ireland, West Virginia, and Maryland. Accompanying these materials are related to exhibition components and ephemera, including a biographical panel, an exhibition poster, and a contents list documenting returned artwork from the Kathleen Ewing Gallery. 

Series 4 consists of digital materials compiled and/or created by Herrera. The series includes folders with titles such as: Bridges of WV; Cars; Mapplethorpe; Pinhole Folder; among others. The digital files largely appear to be reproductions of historical photographic materials, including scans of antique photographs. Formats represented include cyanotypes, pinhole camera images, and traditional film-based photographs that have been digitized.  The files are in their original order.