North American bison arrived around 135,000-195,000 years ago. In the 1500s, there were an estimated 30-60 million bison roaming freely and living in harmony with the native Americans. Unfortunately, in the 1700’s- 1800’s, as Euro-Americans settled the country, moving westward from the east coast, they brought changes to native habitat through plowing and farming. Introduced cattle diseases and grazing competition with feral horses also impacted bison prior to direct impact by Euro-Americans. By

The American Buffalo | Bison or Buffalo? | PBS

Bison vs. Buffalo: What's the Difference?