Why did so little people settle west of the Mississippi River between 1700 and 1800

The land west of Mississippi during the 1700's and most of the 1800' was land that was still dominated by the Native American tribes and the Spanish, and it was not safe at all for people to move in those parts considering the very bad relations with the native populations in that time of period. Also, the authorities, still hadn't tried to motivate people and try to make them settle in those areas with some measure that was going to be attractive for them.

Answer: the Mississippi River was very difficult to cross. If you are in k12 trust me this is right because this shows it is right on my quiz when I submitted it.