There is no single official name for the area from Texas to South Dakota. It's a vast region encompassing multiple states and diverse geographic features.

To give you a more helpful answer, I need more context. What are you interested in learning about this area?

For example, are you interested in:

* Political boundaries? In which case, you might be looking for the "Great Plains" region, which encompasses parts of Texas, Oklahoma, Kansas, Nebraska, South Dakota, and other states.

* Geographic features? You could be interested in the "Central Lowlands" or the "Midwestern United States."

* Cultural or historical significance? There are many different historical and cultural connections within this area, and understanding the specific context will help me give you a more accurate answer.

Please tell me more about what you're looking for!