Salmon Creek Ravine Park in Burien, located a few blocks north of Seahurst Park, is a large, minimally developed park centered on the drainage of Salmon Creek and its small tributaries. The area is forested and has some very large maples and alders, interspersed with Douglas fir, red cedar and madrone.
The park does have some good trails, apparently maintained by local volunteers. But there are no trail signs, and a complete trail map seems to be lacking (as of Summer 2017.) If you hike with a GPS unit and have downloaded the Northwest Topo map, you will find that map helpful.
For the most satisfying hike, begin at the small parking area in the cul-de-sac off Shorewood Drive SW, about 0.35 miles north of SW 131st St.
Other trailheads are mentioned below, and if one of them seems a better option you can easily modify the route suggested here.
Hike past the gate and head gently downhill on the wide trail as it drops into a canyon with many tall, mossy trees and a lot of ferns. Your route will follow this main trail through to Salmon Creek. Along the way, it will offer a number of optional side trips on trails that lead out of the park. You can explore as many of these as your time and energy allow. If you explore them all your round trip hiking route will cover about five miles.
In 500 feet come to the first trail junction. To explore the side trail, head right and follow the small canyon upstream. The trail quickly becomes narrower and more minimal, and you may encounter a few minor obstacles that are easily stepped over. Along the way, an occasional metal cover labeled "Sewer" indicates the presence of a buried pipeline here, but it is very unobtrusive.
In about a quarter mile the trail ends at 16th Ave SW, next to a fire hydrant and a sign proclaiming "Shorewood on the Sound." There are no parking options here. But it's worth noting that Seahurst Park's northern service road entrance, and thus access to its North Nature Trail, is just two blocks south at the dead end of 16th Ave SW. This offers the possibility of extending your hike to include some of the Seahurst Park trails.
Return back down the canyon and continue right on the main trail. In about 750 feet come to another trail junction. To explore the side trail turn right and head up the side canyon. This route, initially a gentle climb, becomes steeper and has a few switchbacks. Soon, it passes through a section bordered by a lot of salal bushes, followed by a short section that offers some invasive Himalayan blackberries. (If you are hiking in summer, a few ripe berries may be available.)
This route emerges abruptly into an open area and joins a graveled extension of SW 126th St about a quarter mile from your main trail. There is no designated parking here, but one or two cars might be able to improvise. (As of summer 2017, there is ongoing construction in the neighborhood so the situation at this trailhead could evolve.)
Return back to your main trail and continue right. In about 900 feet, come to a Y. To explore the side trail, take the right fork. This trail climbs up and, in about 0.2 miles, joins a dead end driveway/extension of SW 124th St. There is room for 2 or 3 cars to park in a wide area here.
Return back to the Y and continue on the main trail. It passes near the site of a major landslide that resulted from the Nisqually earthquake of February 28, 2001. The slide exposed part of an aquifer and formed "Earthquake Creek." You can hear the sounds of the creek below as it continues down the canyon on its way to join Salmon Creek.
Your trail soon descends much more steeply, and you may need to clamber over an old blowdown before reaching a T-junction with a trail that parallels Salmon Creek.
The trail along Salmon Creek can be explored in either (or both) directions, and you will find many large trees and a lot of ferns to appreciate. Like the first side trip trail, this trail shows signs of a buried sewer pipe, but it's a much larger one with entry points that may rise a foot or two above ground level with signs proclaiming "Warning - Sewer Manhole." If this will detract from your enjoyment of the hike, then just skip these trail branches along Salmon Creek.
If you head left from the T-junction, downstream along Salmon Creek, the 0.3 mile trail passes a wastewater (sewer) treatment plant and reaches a trailhead on Shorewood Dr SW, next to the gated entrance to the plant. There is room for two or three cars to park here.
If you return to the T-junction and continue on upstream along Salmon Creek for about 0.35 miles you will come to a Y. The left branch continues on another 600 feet to reach Ambaum Blvd SW (parking options are not good.) In 2017, there were reports that this trail branch had accumulated a lot of debris, not just cans and bottles but old furniture, electronics and mattresses. Perhaps this will have been cleaned up by the time you do your hike.
The right trail branch from the Y leads out 400 feet to SW 122nd St. What little parking is available there is signed with an unencouraging "park at your own risk."
Do either of the side trips along Salmon Creek, then return back to the T-junction next to Earthquake Creek. From there, return to your trailhead the way you came.
During your hike you are likely to hear and see ravens, jays, robins and smaller birds. Squirrel sightings are common. Raccoons also make the park their home, but mostly are nocturnal.
While you are admiring the tall deciduous trees in the park, you may note that a few invasive species also are present, (e.g. ivy, Himalayan blackberry, and bindweed). These are most noticeable near some of the trailheads.
In spring you are likely to see occasional wildflowers, including trillium, avens and youth on age. In early summer these are succeeded by buttercups, foam flower, ocean spray, and a few tall pink penstemons.