The Tiger Mountain Trail (or TMT) traverses the 13,745-acre Tiger Mountain State Forest. The trail was conceived by members of the Seattle Mountaineers (and future members of the Issaquah Alps Trails Club) in 1972 and completed in 1979. It's construction spawned the building many other trails and the establishment of Tiger Mountain as a popular area for recreation.
This Washington Trails Association describes the details of the route (from south to north). It can be completed in either direction as a point-to-point. It meanders through beautiful forest and crosses several creeks as it passes by West, Middle and South Tiger Mountain summits.
Note added 2/4/2022: A small segment of the Tiger Mountain Trail has been rerouted due to logging as of about March 2021. The reroute is approximately 0.4 miles shorter, while the vertical gain has not changed, so the trail may now be slightly easier. We have updated our GPX track.