I stumbled across a very interesting statement on Wikipedia that says:
Despite the treaty, the British kept forts and policies there that supported the Natives in the Northwest Territories. President George Washington directed the United States Army to halt the hostilities between the Natives and settlers and enforce U.S. sovereignty over the territory.
What forts did the British keep in the Northwest Territory?
(And did the United States then seize British-controlled forts by force of arms?)