The largest terrestrial mammal inhabiting the North American continent, the American bison is more commonly known as the buffalo. Herds once numbered in the millions and ranged throughout Great Plains of the United States and Canada and even into the Ohio valley and northern Mexico. Hunted nearly to extinction in the post Civil War years in the latter half of the nineteenth century the species has recovered to the point where it is no longer listed as endangered in the United States. Nevertheless, the estimated population is only about 20,000 in fragmented herds subject to active conservation measures. The largest of these herds, numbering over 4,000, is located in Yellowstone National Park. View is to the ENE in the Hayden Valley along the Grand Loop Road.