Trail Run Project Logo

115th Bypass

 3.0 (1)

0.5 Miles 0.8 Kilometers



39' 12 m


-48' -15 m



Avg Grade (2°)


Max Grade (7°)

403' 123 m


362' 110 m


Shared By Brendan Ross



Getting forecast...

Cut through the middle of Island Center's trail system on this mostly easy route.

Brendan Ross

Dogs Leashed

Features Birding · Fall Colors · Spring

Deer hunting in the main portion of Island Center Forest is permitted for a short period, typically in the second half of October. During this time, the trails are closed to non-hunters. Signs will be placed at trailheads, but if visiting during this period, it's a good idea to check King County's website at…. The Natural and Gateway Areas, east of Landtrust Trail, remain open.

Runner Notes

Island Center Forest's routes are mostly flat and smooth. Road or trail shoes work fine on these easy trails. Expect to share them with other hikers, runners, cyclists, and horseback riders. Take note that there are several singletracks branching off the established trail system and leading to local residents' backyards.

Dogs are not permitted in the Mukai or Meadowlake Pond areas but are allowed throughout the rest of the trail. They are required to remain "either leashed or under strict sight and voice control," according to local regulations.

Generally, visitors should elect to use the 188th Street Trailhead, as it has the most parking. Paper maps are available here and at the Mukai and Cemetery Trailheads.


115th Bypass cuts straight through the middle of Island Center Forest on a north-south route. The northern end of the trail is found about fifty feet east of Techmo, branching off from 115th where the latter turns east. Look for a sign and a huge rock marking the start.

The first quarter mile of the Bypass is a straight shot south on a wide singletrack. The path is occasionally bumpy with rocks of various sizes, requiring runners to pay attention to their footing but not posing any real challenge. The moderately wooded surroundings allow ample sunlight to spill through.

A sign marks the T intersection with 188th, which heads east. Continuing south, the Bypass begins a frequently curving descent, with a brief but moderate decline partway through. The path bottoms out near the Valley of the Firs connector and generally stays flat for its remainder.

After crossing Grinder, 115th Bypass ends a short distance ahead at Cemetery Run, near the Cemetery Trailhead. The interesting Forestry Loop is worth a quick detour to the right or turn left for the fun Fir Hill Trail.

Flora & Fauna

Originally a state-owned area logged to provide revenue for Washington's education system, Island Center Forest was passed to King County Parks in 2002 as a model for sustainable forest management. Owing to its history, the area exhibits a mix of both old growth and restoration areas. Many local tree species grow here, including enormous firs and one of the Island's largest areas of quaking aspens.

Animal life includes smaller woodland creatures and deer, but the biggest draw to Island Forest is the wide variety of birds, more than eighty species in all. The wetland areas around Mukai and Meadowlake Ponds draw bird watchers from around the region.


You & This Trail

Rate Quality

   Clear Rating

Rate Difficulty

Share This Trail

Your Check-Ins



Trail Ratings

  3.0 from 1 vote


  3.0 from 1 vote
5 Star
4 Star
3 Star
2 Star
1 Star


in Washington


2 Views Last Month
42 Since Apr 10, 2016
Easy/Intermediate Easy/Intermediate



Trail Run Project is part of the REI Co-op family,
where a life outdoors is a life well lived.

Shop REI Running