Following service in the Royal Navy during the Seven Years War, Hearne joined the H.B.C. As mate on the sloop Churchill whaling and trading voyage of 1767 and again in 1769 on the Charlotte, during which time Hearne had learned from an elderly Eskimo the tragic fate of the Knight expedition (1719-1721) and had personally seen the relics at Marble Island. After Hearne's two abortive expedition attempts in 1769 and 1770 when, facing starvation, his Indian guides deserted him and he broke his Hadley quadrant, Hearne’s third expedition departed in December 1770.
Entirely dependant on Chipewyan Indians and particularly his guide, Chief Matonabbee (complete with an entourage of eight wives), Hearne became the first white man to traverse the inhospitable Barren Lands. By July 1771 they had descended the Coppermine River to Coronation Gulf; thus Hearne also became the first recorded white man to gaze upon the Arctic Ocean from the North American continent. Despite an error in the location of the river mouth due to inaccurate surveying (no Quadrant), the maps and account of Hearne’s journeys remain the finest description by a naturalist of the terrain and life on the Canadian north to be published in the eighteenth century. Although he did bring back some ore samples, Hearne considered the copper deposits he found to be very small, commonplace and non-viable. This was probably true at the time; however twentieth century technological advances developed them into a successful commercial venture. Hearne’s was one of the first well - documented prospecting expeditions in the Canadian Arctic.
The expedition did much to explode the De Fonte/De l’Isle/Buache theories of a North West passage in low latitude. Hearne’s informative maps were among the first that the H.B.C. made available to cartographers such as Arrowsmith. The maps accompanying the published account of Hearne’s expedition are excellent examples of the ‘way-finder’ type of map as produced prior to the H.B.C.’s employment of properly trained surveyors.
In 1774 the H.B.C., responding to commercial rivalry posed by rival independant fur traders or ‘Pedlars’, selected Hearne to journey 700 miles inland on the Churchill and Saskatchewan River routes to Cumberland Lake and there establish the ‘Company’s’ first inland trading post, Cumberland House, which has been in operation ever since. The following year Hearne was appointed Governor of Fort Prince of Wales.
Even the remoteness of Arctic waters did not save the H.B.C. forts from the effects of the American War of Independence. In August and September 1782, the French allies of the Americans appeared in three ships commanded by the Comte de la Pérouse to force the surrender of Fort Prince of Wales. In spite of its apparent heavy defences, the pragmatic Governor, in the face of a vastly superior and well-trained French force, very sensibly surrendered the fort, along with York Fort, without resistance. During the pillage of the forts, the manuscript of Hearne’s 1770-2 expedition was found, and realizing its historical significance, the gallant La Pérouse did much to encourage its publication.
Following the French attack, during which York Fort was burnt to the ground and Fort Prince of Wales partially damaged, the latter fell into gradual decline. Trade dwindled as a result of the smallpox epidemic that decimated the indigenous Indians who had no immune resistance.
The ruins of the Fort are now a National Historic Monument. A dispirited Hearne returned to England in 1787 mourning the suicide of Mattonabee and the death of Mary Norton, granddaughter of the builder of the great stone fort who had been Hearne’s captivating inamorata. After visiting the family residence in Beaminster, Dorset, he moved to London to work on improvements to the manuscript of his now scarce and justly famous account of his epic journey. It was published three years after his death, from dropsy, in November 1792 at age 47.