Which forts did the British keep in the Northwest Territory after the American Revolution?

Question

At the end of the American Revolution, Britain ceded the Northwest Territory to the US as one of the terms of the Treaty of Paris.

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?)

Answer 1

Great Britain retained six forts in the Great Lakes region after the Treaty of Paris. They remained in British hands until the United States acquired them peacefully through diplomatic means.

The ones located within the Northwest Territory were:

• Fort Miamis, near where Anthony Wayne's expedition defeated Britain's native allies.
• Fort Mackinac, as @CGCampbell mentioned
• Fort Lernoult, aka Fort Detroit, and later renamed Fort Shelby

In addition, Britain controlled these forts in modern New York:

• Fort Niagara
• Fort Oswegatchie
• For Ontario

All of these forts were ceded to the United States by the Jay Treaty in 1796. However, several of them were reoccupied by British troops during the War of 1812.