Hudson Bay is a large body of saltwater in northeastern Canada with a surface area of 1,230,000 km2. It is located north of Ontario, west of Quebec, northeast of Manitoba, and southeast of Nunavut, but politically entirely part of Nunavut.
Although not geographically apparent, it is for climatic reasons considered to be a marginal sea of the Arctic Ocean. It drains a very large area, about 3,861,400 km2, that includes parts of southeastern Nunavut, Alberta, Saskatchewan, Ontario, Quebec, all of Manitoba, and parts of the U.S. states of North Dakota, South Dakota, Minnesota, and Montana. Hudson Bay's southern arm is called James Bay.
The bay is named after Henry Hudson, an Englishman sailing for the Dutch East India Company, and after whom the river that he explored in 1609 is also named. Hudson Bay encompasses 1,230,000 km2, making it the second-largest water body using the term "bay" in the world (after the Bay of Bengal). However, Hudson Bay is the largest in terms of shoreline length, with a shoreline of 12,268 km.
The western shores of the bay are a lowland known as the Hudson Bay Lowlands which covers 324,000 km2. The area is drained by a large number of rivers and has formed characteristic vegetation known as muskeg. Much of the landform has been shaped by the actions of glaciers and the shrinkage of the bay over long periods of time. In contrast, most of the eastern shores (the Quebec portion) form the western edge of the Canadian Shield in Quebec. The area is rocky and hilly. Its vegetation is typically boreal forest, and to the north, tundra.
The coast of Hudson Bay is extremely sparsely populated; there are only about a dozen communities. Some of these were founded as trading posts in the 17th and 18th centuries by the Hudson's Bay Company, making them some of the oldest settlements in Western Canada. With the closure of the HBC posts and stores, although many are now run by The North West Company, in the second half of the 20th century, many coastal villages are now almost exclusively populated by Cree and Inuit. Two main historic sites along the coast were York Factory and Prince of Wales Fort.
According to Wikipedia