The national historic site contains a visitor centre and a largely reconstructed trading post that contains ten structures surrounded by wooden palisades.

The historic site operated as a learning resource for the North American fur trade in the 19th century, with the fort's storehouse having been reopened as a museum in 1931.

The Sto:lo people used the Fraser River as a major source of resources and enabled them to travel and interact with neighbouring Indigenous communities.

[6] Simpson felt such a location would help secure the coast from ocean-based American competition, and believed the Fraser to be more navigable than the Columbia River.

The economic and social patterns adopted by the settlers post-contact illustrates their dependency on the Sto:lo (the original inhabitants of the land).

[10] The first bastion was built by mid-August in order to defend against another attack by the Sto:lo, a second at the end of the month, and the palisade walls were completed in early September.

[6] Some of the Hudson's Bay men were nervous about the Indigenous people of the Fraser, and the bastions were completed first "to command respect in the eyes of the Indians, who begin, shrewdly, to conjecture for what purpose the Ports and loopholes are intended.

[10] During the first few years, trade in furs with the Stó:lō, the Indigenous people (Fraser River), was surprisingly poor from the HBC point of view.

[6] In the first year, guns were in high demand by the Stó:lō to fend off attacks from the Laich-kwil-tach, but when this threat died down, firearms became mainly symbolic yet infrequent items of trade.

Their party found that travel down the Fraser was relatively easy until it forked with the Thompson River, after which the powerful rapids and sheer cliffs convinced Simpson the passage would be "certain Death, in nine attempts out of Ten.

[10] The location of the fort was moved four kilometres upstream in 1839 and changed its focus to farming, fish, and cranberry harvesting, rather than the fur trade.

[10] Catholic Missionary Modeste Demers traveled to Fort Langley and performed religious services for the staff and neighboring Indigenous, baptising over 700 children in 1841.

[10] Due to its strategic location on the northern boundary of the Oregon Territory of the U.S. and in the path of the Fraser Canyon Gold Rush, Fort Langley grew dramatically.

It played a key role in the establishment of the 49th parallel as the international boundary with the U.S. and was the staging point for prospectors heading up the Fraser Canyon in search of their fortune.

The gold rush represented a turning point for many of the Indigenous peoples of the Fraser Valley who experienced a loss of their trading relationship with the HBC and encroachment onto their land by settlers.

[16] The social and political consequences of this influx of adventurers led the British Parliament to establish a crown colony on the Pacific Mainland.

While some might have projected Fort Langley as the capital of the newly created colony, Colonial military commander, Colonel Moody of the Royal Engineers, Columbia Detachment, deemed it militarily indefensible and ordered the construction of New Westminster on the high north bank of the Fraser River many miles downstream due to its much more defensible position.

[17] Douglas made the proclamation on his journey upriver to confront American miners in the wake of the Fraser Canyon War as a pre-emptive move to forestall any drives for annexation to the US.

Parks Canada took control of the site in 1955, and a joint Federal-Provincial program reconstructed three buildings in time for the centennial of the founding of British Columbia in 1958.

[20] The national historic site initially comprised 0.4 hectares (0.99 acres) when it was acquired by the federal government in 1924;[20] although the property grew in size in subsequent decades, including two major expansions.

[22] The northeast bastion is a small irregularly shaped square windows and two doors are situated on its second level, providing access to the wall's galleries.

The Mavis family, who later purchased the land, used it as a barn for a number of years, until Fort Langley was recognized as a site of historic significance in 1923.