The Clackamas River Trail can be completed as a one-way hike with a shuttle, or a very long there-and-back hike in upper and lower sections. This write-up describes a there-and-back hike along the lower section beginning at the Fish Creek Road Trailhead and finishing at Pup Creek Falls. Because the elevation of this trail section is low enough to be snow-free through most winters, it is a good option if higher elevation hikes (such as those on the Indian Henry Trailhead portion of the trail, or even the Riverside Trail) are snowy and impassable.
From the parking area, the trail starts just across the road. It quickly aligns to the riverbank and continues to skirt the river as it proceeds upstream. The trail generally sticks to the north bank of the Clackamas River, winding through dramatic old-growth forests, a few meadow crossings and several good swimming spots. The first of several good swimming holes appears after a half-mile, and an informal campsite is on the right after 2.5 miles. Just before the trail crosses Pup Creek, an unmarked trail splits to the right and continues up the creek for a great view of Pup Creek Falls, a 237-foot, two-tiered waterfall. Turn back here, or if you want a longer hike, continue just over a mile further upstream along the main trail to the turbulent rapid known as the Narrows. This grassy, frequently sunny spot above the Clackamas River is a great place for a picnic and perhaps a swim in the pool below if the rapid if conditions allow.