Fort St John, standing 693 m (2275 ft) above sea-level and situated about 80 km (50 mi.) north-west of Dawson Creek, grew from a fort built in 1806 by the North West Company at the nearby mouth of the Beatton River.
However, archaeologists have established that as long ago as 1794 there was
already a fort at the mouth of the smaller Peace River 8 km (5 mi.) south of the present town center, thus making the town one of the oldest Euro-Canadian settlements on the mainland of British Columbia.
Back in 1793, when he became acquainted with this region during his voyage to the Pacific, Alexander Mackenzie recognized how suitable this spot was for a settlement. When, in 1821, five men from the trading post since set up by the Hudson's Bay Company were killed by Indians the company decided to close the outpost down.
It was not until 1860 that a new fort was built on the banks of Peace River; this was moved several times in the years that followed. In the 1890s a Catholic mission station was attached to the Hudson's Bay Company fort.
During the Klondike gold-rush Fort St John lay on the route taken by the gold-diggers. Around the turn of the century the first settlers also came north to Peace River and realized the agricultural potential of the region. Gradually Fort St John became an important rural center.
During the Second World War an airport and the Alaska Highway were built, resulting in an economic upturn for Fort St John.
In 1952 the John Hart Highway was completed, and for the first time in its history Fort St John had road links with the other major centers in British Columbia.
In the 1950s deposits of oil and natural gas were discovered in the countryside around Fort St John. A large refinery was built in the neighbouring town of Taylor. In addition to agriculture and forestry, the petro-chemical industry developed into an important branch of industry. Furthermore, new coal deposits were found to the south and west of the town.