Old Spanish Trail ID: 2553 | This file appears in: Slave Trade on the Old Spanish Trail Slave trading route of the Old Spanish Trail | Source: Courtesy of the National Park Service. https://www.nps.gov/olsp/planyourvisit/maps.htm. Download Original File SourceCourtesy of the National Park Service. https://www.nps.gov/olsp/planyourvisit/maps.htm. "Old Spanish Trail" appears in: Slave Trade on the Old Spanish Trail