The American Bison were very first animals to arrive at the Monarto Zoo near Adelaide in South Australia when it was set up as an open range zoo in 1983, though I should add that the zoo only opened to the public in October 1993. Before that is was only used as a breeding and pasture area for some animals from the Adelaide Zoo. Since opening to the public it has boomed as far as visitor numbers are concerned, with many hundreds of thousands annually (I can’t find any current figures on their website).
The herd of American Bison has grown from only 2 in 1983 to over a dozen today. They share a paddock of some 15 hectares in size and the bus tours all travel through the enclosure. On some occasions I have been on the bus when the herd has occupied part of the road leading through their home. Stubbornly they usually refuse to move; the driver has no option but to take a slight detour. On these occasions visitors get very close up views indeed. On our most recent visit they were well off the track, thankfully.
Although their numbers in America were originally in the millions they quickly declined due to hunting and disease. Thankfully the species was rescued before they became extinct in the wild and their numbers are now stable, though only about 15,000 exist in the wild population. You can read more about the species here.