The headwaters of the Adams are several unnamed glaciers at roughly 2,000 metres (6,600 ft) elevation in the northern region of the Monashee Range of the Columbia Mountains.

The upper portion of the river flows roughly south and southwest through wetlands and passes through two small lakes, Tumtum and Mica.

A 1977 study by the provincial government along the lower river found sixty-six sites with evidence of habitation dating to 2000 BCE.

[4] The abundance of the salmon run made the river an important food source and trade commodity for First Nations people in the region.

[6] Although prospectors, surveyors, and trappers had travelled the region in the 1800s, the first large scale activity in the river valley by Europeans was logging.

The cut logs were run down the river, then towed in booms by the company owned sternwheeler Helen down Adams Lake.

They complete the arduous trip upstream, including navigating the swift waters and rapids of the Fraser Canyon, in just seventeen days.

They do not eat during this period; instead they rely on fat reserves stored up from heavy feeding in the Strait of Georgia in the late summer.

It is at this point that the salmon take on their distinctive red hue, with the male fish also developing large humped backs and aggressive hooked mouths.

How they are able navigate back to their natal river is not fully understood, but a highly developed olfactory system is believed to play a part.

[9] The alluvial gravel deposits that form the Adams river bottom are ideal for the development of salmon roe and alevins.

According to Canada's Department of Fisheries and Oceans, the Fraser River sockeye run of 2010 was the largest since 1913, numbering an estimated 34 million fish.

In the Globe and Mail, Simon Fraser University biologist John Reynolds said "[predicting salmon numbers] is massively complex, even for a scientist.

The river supports Bald eagle and osprey populations, whose eyries can be seen high up in black cottonwood and dead conifers.

[16] Conservation in the watershed owes much to Roderick Haig-Brown, a Canadian conservationist, writer and a member of the International Pacific Salmon Fisheries Commission.