The Fraser River, 1370 km long, with a drainage basin of 233 100 km2, rises in Fraser Pass on the western slopes of the rocky mountains in the southeast corner of Mount Robson Provincial Park. It first flows slowly northwest in meandering channels along the flat valley floor of the rocky mountain trench to Prince George, BC, where it bends to a southward course. The gravel banks of the Fraser then increase in height to 50-100 m, where the river has cut down into the glacial deposits of the central Interior Plateau; the river's velocity of flow increases south of Prince George as it is joined by several tributaries, the largest being the Nechako River from the northwest.

The Fraser enters the Fraser River Canyon south of Quesnel, where it is joined by the Chilcotin River from the west. Here the river has cut down 300-600 m into the bedrock of the Interior Plateau. In this middle section the Fraser is joined by other large tributaries such as the Quesnel and Thompson rivers from the east and the West Road River from the west. At Hells Gate, south of Boston Bar, the river narrows to 35 m. At the southern end of the canyon, near Yale, the river flows between the north end of the Cascade Mountains to its east and the Coast Mountains on the west.

At Hope the Fraser is only about 5 m above sea level, though this height varies seasonally. Its average annual flow here of 2720 m3/s varies between an average low of 867 m3/s in March and an average peak flow of 6970 m3/s in June. The Lower Fraser River bends westward at Hope and its valley broadens into a delta that is about 50 km wide, where the river empties into the Strait of Georgia. The southwestern part of the Fraser delta is in Washington state, US.

The river was named by David Thompson after Simon Fraser of the North West Company, the first European to follow its course to its mouth in 1808. Little use was made of its central portion, because of its turbulent currents, until the discovery of gold on sandbars north of Yale set off the Fraser River Gold Rush in 1858. The Cariboo Gold Rush, which followed to the north, brought the first narrow road (Cariboo Road), carved into the canyon walls, and later the Canadian Pacific Railway followed the gash of the Thompson-Fraser rivers as the only low-level route through the Coast-Cascade mountain barrier to southwestern BC.

The Fraser River basin is well forested in its central sections, but has grassland vegetation and cattle ranching in the southwest along the Chilcotin River and in its dry lower altitudes, as near Ashcroft. Numerous large sawmills and pulp and paper mills are the basis of the urban economies in the largest cities of Kamloops, Prince George and Quesnel. Mining of gold, copper, molybdenum and mercury has flourished at various times and places throughout the basin. The headwaters of the river's many tributaries are the spawning grounds of pacific salmon, which are caught later off the mouth of the Fraser.