Mount Defiance
I-90 CorridorBest Jul–Sep
An honest I-90 climb to a 5,584-foot summit with Rainier, Baker, and two quiet lakes below.
About This Trail
Mount Defiance anchors the southern skyline of I-90 west of Snoqualmie Pass, and its summit delivers one of the best view rewards in the corridor for the work involved. The route climbs the Ira Spring Trail through thick forest, crossing Mason Creek on an installed footbridge, before opening onto meadows below Bandera Mountain. At Mason Lake, a quiet tarn cradled by heather benches, most hikers stop. Those continuing turn west on Mount Defiance Trail #1009 and grind another two miles up an exposed ridge.
From the 5,584-foot summit the Cascade skyline unfolds: Rainier dominates to the south, Adams stands distant behind it, Baker floats to the north, and Mason Lake and Lake Kulla Kulla glint below. In July the upper slopes bloom with glacier lily, beargrass, Indian paintbrush, and lupine.
Expect sustained climbing on rooty, occasionally boggy tread. Snow patches linger on the east slope into July. FR 9030 closes for winter, so plan the full season window between late June and early October.
Seasonal Highlights
Astronomy
Trail Conditions
“I parked at exit 42 since the road was closed and headed up the connector trail to the road.”
Last report: Mar 28, 2026
Scorecard
Large parking lot fills early on summer weekends. Mason Lake draws most traffic; the summit push thins it out.
Permits / Passes
Safety & Considerations
Today's Hazard
- Strong sun — sunscreen, hat, and sunglasses recommended; water reflection adds glare near the lake
Persistent Hazards
- FR 9030 closed for winter
- Snow lingers on the east slope into July and obscures tread
- Rooty, boggy lower trail is slick in wet conditions
Getting There
Large Ira Spring Trail lot at the end of FR 9030. Fills early on weekends. Northwest Forest Pass required.
Recent Reports
Arrived around 9:00am at the exit 42 TH. Probably 10 cars present, didn't see a soul until reaching Mason Lake.
I knew I wouldn't be getting all the way to either Mason Lake OR Mount Defiance but decided to give er a go. I parked at exit 42 since the road was closed and headed up the connector trail to the road.
The road to Ira Spring trailhead is officially closed so you should park on the north side of Exit 42. This means a steep 0.