Hudson Bay (Inuktitut: Kangiqsualuk ilua,French: baie d'Hudson), sometimes (usually historically) called Hudson's Bay, is a large body of saltwater in northeastern Canada. It drains a very large area, about 4,041,400 square kilometres (1,560,400 sq mi), that includes parts of Ontario, Quebec, Saskatchewan, Alberta, most of Manitoba, southeastern Nunavut, as well as parts of North Dakota, South Dakota, Minnesota, and Montana. The southern arm of Hudson Bay is called James Bay.

The Eastern Cree name for Hudson and James Bay is Wînipekw (Southern dialect) or Wînipâkw (Northern dialect), meaning muddy or brackish water. Lake Winnipeg is similarly named by the local Cree, as is the location for the City of Winnipeg.

Hudson Bay encompasses 1,230,000 square kilometres (470,000 sq mi), making it the second-largest bay in the world (after the Bay of Bengal). The bay is relatively shallow and is considered an epicontinental sea, with an average depth of about 100 metres (330 ft) (compared to 2,600 metres in the Bay of Bengal). It is about 1,370 km (850 mi) long and 1,050 km (650 mi) wide. On the east it is connected with the Atlantic Ocean by Hudson Strait; on the north, with the Arctic Ocean by Foxe Basin (which is not considered part of the bay), and Fury and Hecla Strait. Geographic coordinates: 78° to 95° W, 51° to 70° N.

Hudson Bay is a town located in north-east Saskatchewan, Canada.

In 1757, a fur trading post was established in the Hudson Bay District, beside the Red Deer River. Ruins from the post have been found near the village of Erwood. In 1790, the North West Trading Co. set up a trading post at the mouth of the Etomami River. Speculators think that a South Company's post was set up on the opposite mouth of the River, where there are remains of a 2nd post unaccounted for.

Over the years a settlement grew and in July 1907, an application was made to erect Etomami as a village. (Etomami was a native word that meant a place where 3 rivers join.) But in order to establish a hamlet, it was necessary to have fifteen occupied dwelling houses. By August, the list was completed and the village was formed. Mr. B.F. Noble was the first "overseer" of the village. The post office was also established at that time. It was located on the 100 block of Churchill Street. Then in 1909 the Canadian Northern Railway Company chose the name, Hudson Bay Junction, so the name was changed.

The Hudson Bay Lowlands is a large, poorly drained piece of wetlands wedged between the Canadian Shield and southern shores of Hudson Bay and James Bay. Many wide and slow-moving rivers flow through this area toward the salt water of Hudson Bay. Mosquitoes and black flies thrive here. This is a sparsely populated region. There are a few small First Nations settlements on the southern shore of Hudson Bay at places like Moose Factory, Moosonee, and Fort Severn. The Lowlands also make up a portion of Canada's oil and natural gas production.^{[citation needed]}

The local Ojibwa and Cree most likely came into contact with the region but did not populate the region due to the harsh, undesirable conditions and poor drainage patterns of the area. When Europeans arrived in the area, The Hudson's Bay Company set up trading posts such as Rankin Inlet, some of which remain populated until today. However, these never grew into sizable towns, again because of the poor living conditions and climate. To this day, not all of the lowlands have been properly explored.

The Hudson Bay expedition of 1686 was one of the Anglo-French conflicts on Hudson Bay. It was the first several expeditions sent from New France against the trading outposts of the Hudson's Bay Company in the southern reaches of Hudson Bay. Led by the Chevalier de Troyes, the expedition succeeded in capturing the outposts at Moose Factory, Rupert House, Fort Albany, and the company ship Craven.

Although France and England were then at peace, war broke out between them in 1689, and the conflict over the Hudson Bay outposts continued. One of Troyes' lieutenants, Pierre Le Moyne d'Iberville, made further expeditions against HBC holdings; these culminated in the French victory at the 1697 naval Battle of Hudson's Bay. At the end of the war, the French controlled all but one of the company's outposts.

In 1679, French explorer Pierre-Esprit Radisson and financier Charles Aubert de La Chesnaye met in Paris, and laid the foundations for the establishment of a fur trading company they called the Compagnie du Nord. Its objective was to engage in fur trade in northern North America, where the English Hudson's Bay Company (HBC) had realized significant profits in that business. The Compagnie's first major expedition in 1682 successfully seized York Factory. After the Compagnie's profits were virtually wiped out by taxes imposed by authorities in New France, Radisson entered service with the HBC, and led several profitable shipping expeditions to Hudson Bay, including recovering for the company York Factory and the furs taken there.