Great Plains is the easternmost territory in the original game, bordered on the west by Tall Trees. The northern, southern, and eastern borders of the region consist of the shoreline of Flat Iron Lake. The Upper Montana River forms the northern border of the territory, with Big Valley on the other side.
The landscape of Great Plains consists primarily of rolling hills with low-lying vegetation and few trees. As such, Great Plains has the largest population of plants in one area, in all of the original game. Due to the landscape and the visual distinctiveness of the plants, they are also among the easiest to find.
This region is named after and based off the real-life Great Plains, a plains region which covers a broad geographic range extending from the southern United States in Texas to the western provinces of Canada. However, based on the presence of Plains bison, which were almost extinct in 1899, it can be narrowed down to a few possible locations including the Oklahoma-Kansas border, eastern Colorado, southern Wyoming, and northeastern Montana.