Since time immemorial, the Children of the Plains, the Blackfoot, have roamed a traditional territory that stretched from the North Saskatchewan River in Alberta and Saskatchewan to the Yellowstone River in the state of Montana, from the Continental Divide in the west to the Great Sand Hills in the province now known as Saskatchewan.
Siksika Nation
As can be seen from the above, the Blackfoot occupied parts of Alberta, Saskatchewan and Montana, the majority of their traditional territory being north of the 49th parallel, in Canada. The map below shows the extent of their territory.
For half my life I lived in the area once part of the Blackfoot Territory and have travelled throughout the majority of it. One area I've visited which struck me as being quite similar to that depicted in the first panel of the comic strip reproduced below is that of the bluffs at
Writing-on-Stone Provincial Park, which is in Alberta, just north of the border with Montana. These sandstone bluffs, known as hoodoos, were well known to the Blackfoot. Near the western edge of the traditional Blackfoot hunting ground, they left dozens of pictographs and petroglyphs on these hoodoos as witness to their presence. This is actually one of the very few places in their territory which have this appearance. Compare in the photos below.
Incidentally, the cacti depicted in the comic are about 1,000 miles too far north. They are saguaro, which are not to be found north of Arizona.