You could have googled it yourself.

http://www.eatfoodforlife.com/contact/

Any grocery with a dedicated health food section should have some examples of Bison meat, but it will be limited portions and frozen. I have no trouble buying it in the Midwest, even in towns with under 50,000 population.

Whole Foods would certainly have some.

If your wanting fresh or select-a-cut, see @elbanditoroso,s answer.