In the 18th century the thrust of exploration was spearheaded more by fur traders and the military than by the religious. To hold its territory, France began establishing posts in the Illinois country, Louisiana and the west, posts that would have a military function and that would enable it to control the fur trade of the interior. Various members of the La Vérendrye family were fully involved in these activities, and in the search for the Western Sea— a mythical body of water that dominated French geographical thinking at the time. Pierre Gaultier de Varenne et de La Vérendrye (1685–1749), a military officer, was stationed on Lake Superior in the 1720s and in 1731 obtained a three-year monopoly on furs from the west. Helped by his sons and a nephew, he had built a number of posts on Lake of the Woods, Rainy Lake and Lake Winnipeg. Their explorations reached as far as the lower Saskatchewan River and south into the Mandan country. Two of the sons, including Louis Joseph Gaultier de La Vérendrye (1717–61), the Chevalier, spent over a year in 1742–43 exploring south and west and reaching as far as what is now Wyoming. They had with them a lead plaque bearing a Latin dedication to Louis XV on one side; on the other they evidently engraved their own names and the date March 30, 1743. They buried the plaque at Pierre, South Dakota. It was not found until 1913.

In the wake of their victories over the French at Quebec in 1759 and Montreal in 1760, the British began extensive surveys of all their holdings. Much of the work was divided between Samuel Holland, Joseph Frederick Wallet DesBarres, and James  Cook. DesBarres (1722–1824) charted the coastal areas around Nova Scotia, while Holland was working in the Gulf of St. Lawrence and Cook around Newfoundland. DesBarres published his Atlantic Neptune, an atlas based on 10 years of work and including some maps based on surveys made by others, between 1777 and 1781. Three years later DesBarres became the first lieutenant governor of Cape Breton, but he managed to alienate many of the settlers with his autocratic and irascible manner. Recalled in 1787, he agitated over the next decade and a half for another appointment until at the age of 81 he was made governor of Prince Edward Island, a position he kept until the age of 90.

James Cook (1728–1779) was thought to be the greatest seaman of his time. After working in Newfoundland, he undertook two monumental expeditions, circumnavigating the world in 1768–71 and 1772–75 and returning with solid new evidence about the geography of the South Pacific. The fact that he was able to keep his crew free of death from scurvy during these voyages also brought fame and in 1776 he became a fellow of the Royal Society. That July he undertook a voyage in search of the Pacific entrance of the fabled Northwest Passage. The ships sailed east and over a year and a half later arrived off the coast of British Columbia, where the crew spent several weeks at Nootka Sound. After sailing north along the coast until beset by ice, they wintered in the Sandwich Islands (Hawaii) where Cook was killed in an altercation with local inhabitants.

George Vancouver (1757–98) sailed with Cook on both the 1772–75 Pacific expedition and on his final expedition. Plans for further west coast explorations in 1790 were interrupted by the Nootka Sound Affair when several British ships were taken by the Spanish who were trying to claim exclusive trading rights to the rich furs of the area. After Britain successfully upheld its position, the planning resumed and Vancouver took charge of the expedition. He arrived at the west coast in April, 1792, and— in a pattern presaging the wishes of those who were to follow him—spent three summers surveying the coast of North America and three winters in the Sandwich Islands. Vancouver Island commemorates his name. His A Voyage of Discovery of the North Pacific Ocean, and Around the World... was published in 1798.

At the same time as these coastal explorations were being undertaken, the interior and the Arctic were being explored, mostly by fur traders. In fact, in 1789 Alexander Mackenzie travelled from Lake Athabasca down the river that bears his name to the Arctic; a few years later, in 1793, he was the first European to travel overland to the Pacific. After the end of the Napoleonic Wars, however, the British government again became interested in the quest for the Northwest Passage and the Admiralty sent out expeditions in 1818 and 1819–20. Yet it was in fact, however, the search for Sir John Franklin that brought the greatest knowledge of the area. Franklin (1786–1847) took part in mapping expeditions to the Arctic in 1821 and 1825–27 and then in 1845 was sent with the Erebus and the Terror to continue this work by navigating the Northwest Passage. He was never heard from again, and between 1848 and 1859 numerous expeditions were sent in search of him. Eventually it was established that the ships had been caught in the ice in Victoria Strait and all members of the crews had died. They had discovered the elusive Passage although this fact was not known for some years.