Black Diamond Open Space

Covering 1,240 acres, this natural area offers 17 miles of multi-use trails, streams, wetlands, and peat bogs. It also hosts a protected migratory corridor, the Wildlife Habitat Network. Enjoy walking, bicycling, studying nature, or horseback riding.

getting there


Black Diamond Open Space is accessed via SR-169, between the communities of Maple Valley and Black Diamond. There are two gravel parking lots off SR-169/Maple Valley-Black Diamond Rd SE/3rd Ave.  The southern parking lot is the main parking lot. It is located on the east side of SR-169 and is suitable for cars, trucks, and horse trailers. The northern parking lot is smaller and is located on the west side of SR-169. It can accommodate cars and trucks only.


about the natural area


King County Parks is actively restoring the health of the forest with periodic stewardship activities such as invasive weed removal, thinnings, and plantings. Prior to public-ownership, portions of the forest in BDOS [Black Diamond Open Space] were clear-cut. King County Parks replanted the forest in 2014. During this lengthy transition, forests can sometimes look a little scruffy. Active forest stewardship increases resilience to droughts, pestilence, and wildfire and makes for better habitat and ecological diversity. BDOS is a Forest Stewardship Council® (license code FSC-C008225) certified working forest.

BDOS straddles two distinct watersheds. The Cedar River Watershed and the Green River Watershed.  Rock Creek, a fish-bearing stream runs through the site which drains to Cedar River and out to Puget Sound. Ravensdale Creek also flows through the site, eventually draining to the Green River which eventually joins Duwamish River and into Elliott Bay. These waters are valuable for cutthroat trout, coho, sockeye, and chinook salmon. The presence of beavers and freshwater mussels are indicators of good water quality.

on the trail

Explore some or all of the 17 miles of interconnected trails and loops in the natural area.


  • Visit the Black Diamond Open Space web page for a map and more information.
  • A large number of the trails state the bicycles have the right of way. This is in contrast to the typical right of way rules.
  • Suitable Activities: Day Hiking, Trail Running, Naturalist
  • Seasons: Year-round
  • Weather: View weather forecast
  • Difficulty: Easy
  • Land Manager: King County Parks & Recreation
  • Parking Permit Required: None
  • Recommended Party Size: 12
  • Maximum Party Size: 12
  • Maximum Route/Place Capacity: 12
  • see Land Manager
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