The Great Plains is a grassland region in North America which lies between the Mississippi River and the Rocky Mountains and includes parts of Oklahoma, Texas, Kansas, Colorado, New Mexico and Nebraska. It also stretches north into Canada. The region covers an area of approximately 1,3000,000 square kilometers and was home to migrating American Bison herds until the late 1800s. The climate varies greatly throughout the year, with very hot summers and extremely cold winters. The region is of growing importance in the generation of wind power.