What were the middle grounds, and how did conditions there differ from conditions in the colonies along the atlantic seaboard?

The place where two populations are living together and they have their own rules, power and government, this is known as the Middle grounds. The middle grounds by with the Atlantic seaboard had to rearrange or to find the group that is controlled by the Europeans. In nineteenth century, the middle grounds are abolished and this make the place for the Europeans in which Indian were cold-heartedly troubled.