There is a published guide to these microfilm holdings:

Caballero, Cesar, Susana Delgado & Bud Newman, MEXICO AND THE SOUTHWEST: MICROFILM HOLDINGS OF HISTORICAL DOCUMENTS AND RARE BOOKS AT THE UNIVERSITY OF TEXAS AT EL PASO LIBRARY. El Paso: UTEP Library, Special Collections Dept., 1984.

Though the guide was published awhile back, it will introduce you to the bulk of the records there. Because specific collection indexes and inventories are spotty, check with the library's Microforms Dept., (915) 747-5681, or with Special Collections, 747-5697 for specific information.

Some of the non-ecclesiastical collections, as listed in the guide, include:

• Archivos del Ayuntamiento de Chihuahua, 1712-1941. (656 rolls)
• Cd. Juarez, Chihuahua Municipal Archives, 1726-1899 (c. 91 rolls)
• Archivos Historicos del Gobierno del Estado de Durango, 1578-1847.

  (374+ rolls)

Hope this helps!

Ann Massmann
(former Acting Head, Special Collections, UTEP Library)

Southwest Studies Librarian
Center for Southwest Research
University of New Mexico
Albuquerque NM 87131-1466
massmann@unm.edu

(NOTE: I am new at the UNM Library, and will be glad to help researchers with reference questions applicable to the borderlands, New Mexico, and the Southwest.)