It rises at Mountain Meadow Lake near the 9,008 ft (2,746 m) peak of Granite Chief in the Tahoe National Forest.

Flowing initially northwest, the river soon swings west into a gorge, paralleling the Forest Hill Divide on the south.

Big Granite Creek then joins the North Fork of the American River coming in from the right.

About 4 miles (6.4 km) downstream, it receives Shirttail Creek from the left then is impounded in Lake Clementine (or North Fork Lake) which is formed by the North Fork Dam, built in 1939 to contain hydraulic mining debris.

[4] Below the dam, the river bends south, passing under the Foresthill Bridge, the highest bridge in California, then receives the Middle Fork American River, its largest tributary, from the left.