The Fraser drains a 220,000 km² area. Its source is near Yellowhead Pass, and for the first part of its course it runs northwest, reaching past 54° north before making a sharp turn to the south. At the city of Prince George it is joined by the Nechako River, then continues south and slightly east until just north of the United States border, where it issues from the Coast Mountains from a deep canyon (the Fraser Canyon) a few hundred miles long. It then turns west through a lush lowland valley, known as the Fraser Valley, past Chilliwack, Abbotsford, Mission and the eastern suburbs of Vancouver. After 100 kilometres, it forms a delta where it empties into the Strait of Georgia between the mainland and Vancouver Island. The lands south of the City of Vancouver, including the cities of Richmond and Delta sit on the flat flood plain. The river's volume at its mouth is 112 km³ each year, and it dumps 20 million tons of sediment into the ocean.

The Fraser is heavily exploited by human activities, especially in its lower reaches. Its banks are rich farmland, its water is used by pulp mills, and a few dams on some tributaries provide hydroelectric power. The main flow of the Fraser has never been dammed so as not to interfere with salmon spawning. Today, Fraser Herald at the Canadian Heraldic Authority is named after the river.

The delta of the river, especially in the Boundary Bay area, is an important stopover location for migrating shorebirds