From its headwaters in the Warm Springs Indian Reservation near Abbot Pass in the Cascade Range, the river flows generally west through Mount Hood National Forest in Clackamas County to the unincorporated community of Ripplebrook.

Campgrounds on the lake shore to the left include Oak Fork, Gone Creek, Hood View, and Pine Point.

[4][5] The United States Geological Survey monitors the flow of Oak Grove Fork at two stations, one below Timothy Lake, 15.5 miles (24.9 km) from the mouth, and the other above a Portland General Electric (PGE) power plant intake, 6.7 miles (10.8 km) from the mouth.

[8] At the power plant gauge, the average flow is 486 cubic feet per second (13.8 m3/s) from a drainage basin of 124 square miles (320 km2).

[citation needed] As part of its efforts to generate electricity from water power in the Clackamas River basin, PGE built a dam on the Oak Grove Fork in 1923.

To regulate flows on the Oak Grove Fork and on the mainstem Clackamas River, the company built a dam at Timothy Meadows, upstream of Harriet Lake, in 1956.