In 1858 gold found along the Fraser and Thompson rivers brought a rush of miners, mostly from the USA, into what soon became the Colony of British Columbia. As prospectors spread throughout the colony, many other gold rushes ensued, including to Rock Creek and the Boundary country. At the same time miners were active in what is now Washington State. It was easy for the miners on both sides of the British Columbia-US border to travel between the two jurisdictions along the natural routes that follow the mountain valleys and trenches which run north and south. In particular, the Okanagan Valley, Columbia River and Kootenay River served this purpose, much to the annoyance of Governor James Douglas who realized that men taking these routes could easily evade payment of duties and mining license fees. He preferred that miners and merchants should travel to Victoria or New Westminster, pay their fees and buy their supplies there before continuing into the gold regions.

Douglas ordered the Royal Engineers to survey a suitable route from Hope on the Fraser River eastwards to Rock Creek and in 1860 gave the responsibility of building the trail to Edgar Dewdney, a young civil engineer. Dewdney started work on the trail at Hope early in 1860 and almost immediately ran in to problems with the Royal Engineers, as his plans did not agree with their ideas of an adequate trail. Because of these problems, Dewdney left the project, forcing the Royal Engineers to complete the work to Princeton on their own.

In the spring of 1861, Dewdney returned to the trail, joined by another engineer, Walter Moberly - minus the aide of the Royal Engineers. Employing civilians, the trail progressed quickly along the route, now occupied by Highway No. 3, to Rock Creek. However, by that time the gold had been exhausted and the miners had left the area for the richer fields of the Cariboo.

Later gold discoveries, notably at Wild Horse Creek in the East Kootenays in 1864, was the motivation for extending the Dewdney Trail farther east. In 1865 BC’s Governor, Frederick Seymour (who had replaced Douglas in 1864) approached Edgar Dewdney to do the work. Work crews under Dewdney’s direction started at several places along the route. By the fall of 1865 the trail to Wild Horse was almost complete, though it needed improvement along many stretches. However, the trail proved less important than anticipated, mainly because the gold at Wild Horse soon ran out and most of the miners moved on to other promising regions such as the Big Bend on the Columbia River. Transportation into the East Kootenay region continued to rely on routes through the USA.

Today the Crowsnest Highway (Highway 3) across southern British Columbia follows the general route of the Dewdney Trail and actually straddles it in several places. Other sections of the Dewdney Trail are intersected by other roads, transmission lines and railways or have been obliterated by logging and mining activities. Nevertheless, portions of the trail do exist and have been developed for recreational use. Parts of the trail have been incorporated into the Trans Canada Trail.