I. US-Mexico Projects with a digital component
II. Nineteenth century (1800-1899)
Includes projects from the entire states.
1) U.S. border states include California, Nevada, Utah, Colorado, Arizona, New Mexico, Texas, Louisiana and Florida
2) Mexico border states include Baja California, Sonora, Chihuahua, Coahuila, Nuevo León and Tamaulipas.
III. Twentieth and twenty-first centuries (1900-Present)
Includes projects from the cities and counties located along the current division line from California, Arizona, New Mexico, Texas, Baja California, Sonora, Chihuahua, Nuevo León and Tamaulipas.