Final answer:
Nomadic cultures of Native Americans were prevalent in the Great Plains region before the 1800s, largely due to the reintroduction of the horse which aided in bison hunting.
Step-by-step explanation:
In which region would you have been most likely to find nomadic cultures of Native Americans before the 1800s? You would have most likely found nomadic cultures of Native Americans in the Great Plains region before the 1800s. This region offered vast herds of bison, which the Plains groups followed and hunted. The transformation from agriculturalists to nomadic hunter-gatherers among these groups was facilitated by the reintroduction of the horse to North America, which significantly increased their mobility and ability to track bison herds. Prior to the arrival of Europeans, there were already diverse Native American groups across North America, many of which had distinct subsistence strategies reflecting their region.