Things to Do

This 5 mile trail is very scenic and you will enjoy the sight and sounds of the rushing river. The lush rainforest ecology here is due to the annual 140 inches of rainfall, upriver in the Olympic Mountains!
The beautiful Duckabush Valley has been very geologically active and bears many marks of glaciers. You will see huge glacially deposited moss-covered boulders left by the Duckabush Glacier during the last Ice Age. Thousands of years later, an old logging railroad early in the twentieth century was used here to drag out huge old-growth trees, mostly Douglas Fir, Madrone and Maple. Rusty logging cables and a few old rails lie beside the trail to tell their tale. Children can still find and touch them. The first 2½ miles of this trail are gentle enough for children, and are lush with forest ferns, moss, flowers, and berries.
http://www.fs.fed.us/r6/olympic/recreation-nu/trails/Duckabush.pdf
Getting there — On U.S. Route 101, about 15 miles south of Quilcene or 37 miles north of Shelton, turn at milepost 310 onto Duckabush River Road (Road 2510), signed Duckabush Recreation Area. Continue 6 miles (the first 3.5 miles are paved). Pass Collins Campground at 5 miles, pass a horse unloading area and then turn right on Road 2510-060 (This is a small sign on your right) to the trailhead and facilities, elevation about 440 feet.
Duckabush River Trail: Take FS Road #2510 for 6 miles to FS Road #2510-060 and the trailhead. At trailhead: vault toilet, parking, registration, wilderness permit box for Olympic National Park. Access Park trail via USFS Wilderness Trail #803, which includes 1,000 foot ascent over Big Hump. River Ford at Upper Duckabush can be hazardous to cross in spring and early summer. The grade gets steeper in climb to subalpine headwaters at Marmot Lake and then O’Neil Pass. Marmot Lake 201 miles; O’Neil Pass 21.3 miles from USFS Duckabush Trailhead. National Park overnight fees required. Trail Park pass required. For more info, call Wilderness Information Center: 360-452-0300, Hood Canal Ranger Station: 360-877-5254; Staircase Ranger Station: 360-877-5569.
The first mile or so climbs gently past the Brothers Wilderness boundary. Then it makes it way down to the roaring Duckabush River. After a short stretch along the river, we made our way towards Big Hump. The high point of Big Hump is at about 1700 feet. This is the steepest part of the run. Beyond Big Hump we followed the meandering trail through pristine virgin forest. This section of the trail is gently rolling and it gradually makes its way down to 5-mile campground. 5-mile campground sits along the impressive rapids of the Duckabush. We snapped some photos and decided it was time to start our reverse run back to Big Hump and down to the trail head. (Special note for motivated mountain runners: You can continue past 5-mile campground for 17 more miles all the way to O’Neil Pass, elevation 4950 feet.)
You are very near the start of an advanced Duckabush River 21-mile backpacking hike into the mountains, for more info about that adventure see Trails.com:
http://www.trails.com/tcatalog_trail.aspx?trailid=HGW136-038

Take a firsthand look at history from 100 years ago at Ranger Hole Trail. The hike is just 1.6 total miles, mostly flat, but very steep down to the river. Moderate difficulty. Views of waterfalls can be seen from Ranger Hole, so named because rangers posted at the guard station used to fish for Steelhead there in the deep river “hole”.
There is a small picnic area and toilet at the trailhead.  A Northwest Forest Pass or Interagency Pass (Annual, Senior or Access) is needed to park at the trailhead.
The trail here at the historic Ranger Fishing Hole has two parts and will really appeal to children—one part features the historic ranger’s cabin and signs telling about life in the early 1900s, and another part leads to a stunning overlook of a loud white-water rapid of the gorgeous pristine Duckabush River. An abundance of ferns and mosses along the way provide a lush understory of plants in a conifer stand of trees.
Directions: South of the town of Brinnon, take Forest Service Road #2510, 4 miles to the end of pavement. Ranger Hole Trail is on the left, near the vintage Interrorem Cabin.