Whew, does this not give any background at all. Background essential to knowing what happened.
To start with, when the British colonies were established on the coasts, westward expansion was effectively blocked by the northern and southern tribes, except that in pre-history, they had such an enormous and bitter war, that they had agreed that most of the area of what is now Kentucky was a “neutral zone”, prohibited to both sides.
So when new immigrants, particularly tough Scots-borderers arrived, they were encouraged to settle in Kentucky, making an effective wedge between the northern and southern tribes. Once established, neither Indian confederation could drive them out. So a westward expansion corridor was created.
The next big problem came with the Louisiana Purchase, which included vast areas claimed by the Plains Indians. But these claims were problematic, as there were far too few Plains Indians to control such an area except intermittently. Settlers could easily move in and set up defenses before their presence was detected.
Then came Andrew Jackson, who though he had fought side by side with Indians against the French, had no problem in ordering a massive “ethnic cleansing” of the southern tribes, pushing them West across the Mississippi. The infamous “Trail of Tears”.
The next phase of westward expansion was conducted to a great extent with considerable tact and diplomacy by the US military, whenever they could, who generally rejected the anti-Indian hatred devolved from Washington.
But at the same time, the US military was well aware that it faced several very large and reasonably capable armies of the western tribes, most of whom were more than willing to go toe-to-toe with them in a fight.
Much of this came to a head with a withdrawal of many US Army forces because of the Civil War. But after the war was over, the battle hardened Army went West with resolve and broke the resistance of the western tribes during the Indian Wars. The last skirmishes ended just before the turn of the 20th Century.
Just for the record, Andrew Jackson never fought against the French. He was a mere Carolina lad of 7 years when the first shots of the Revolutionary War were fired at Lexington Green. He was a early teenager when he first encountered a British soldier in that war and acquired a hatred for them which would last a lifetime.
His cruel policies toward Indians were a natural outgrowth of his seeing them as allies and collaborators to the British to limit American expansion.