Final Answer:
Manitoba joined Canada in 1870, while the Northwest Territories joined later in 1870 and 1877.
Step-by-step explanation:
Manitoba formally joined Canada in 1870 through the Manitoba Act. This act was a result of negotiations between the Canadian government and the Red River Métis, led by Louis Riel. It established Manitoba as a province within Canada, with its own government and official status.
The Red River Rebellion in 1869-1870 played a crucial role in pushing for these negotiations, emphasizing the need for the region's inclusion within the larger Canadian federation.
The Northwest Territories, on the other hand, became a part of Canada in stages. Initially, the Hudson's Bay Company had control over the area. However, in 1870, a vast portion of the Northwest Territories was transferred to Canada by the Rupert's Land Act and the North-West Territories Act. This transfer followed the acquisition of Rupert's Land from the Hudson's Bay Company. Subsequently, in 1877, more areas were added to the Northwest Territories, expanding its territorial jurisdiction.
These events mark significant moments in Canada's history, reflecting the country's expansion and the ongoing negotiations between the Canadian government and various indigenous and settler communities in the late 19th century, leading to the incorporation of these regions into the Canadian federation.