The term Vast Prairie is a descriptive phrase used to refer to the Llano, a large grassland region located in the south-central United States. The Llano is characterized by its expansive, rolling hills and wide open spaces, making it an ideal habitat for a variety of wildlife. It is also home to a number of small towns and ranches, making it an important part of the local economy. The Llano is a unique and beautiful landscape that has been preserved for generations.