To accurately identify the region indicated by the number 1 on the map, I would need to see the map in question. However, if you're referring to common geographic regions in a specific context, the Piedmont is typically known as a region located between the Coastal Plain and the Appalachian Mountains in the eastern United States. The Blue Ridge and Appalachian Plateau are also well-defined regions.
If you can provide more context or descriptions from the map, I would be happy to assist you further!