Sulphur Mountain Trail is a 10.9 mile lightly trafficked out and back trail located near Darrington, WA that features a lake and is rated as difficult. The trail is primarily used for hiking, walking, nature trips, and birding and is accessible from June until September.
(Description from WTA website) This trail has a brutal elevation gain in a short time, but the views from the peak of Sulphur Mountain are worth the climb. On maps, the Sulphur Mountain trail renders as a long squiggly line that gains 4200 feet in 5 miles, so be prepared to do lots of squiggly climbing as the trail switchbacks up an average 16 percent grade through forest before it breaks out into open hillside just a short distance before the official trail ending and your very first chance of unobstructed views to the south and west. Due south is the magnificent northern face of Glacier Peak. Below you to the north you will see Sulphur Lake and the remnants of a silted in Lookout Lake. Trails lead down to the lake and around the rim to Sulphur Mountain across the basin from to the south-east. There is no water on the trail so bring plenty of your own. You can expect to have very few encounters on this trail so if you enjoy solitute, and a good work-out this trail is for you.
A little over 10 miles round trip and 4200ft gain make for a workout of a hike. 99% of the trail climbs relentlessly through the forest offering little to no views until you reach the very top. Numerous blow-downs of large trees to climb over or around. The good news is that the trail is pine needle and dirt almost the entire way to make it easier on the feet. The views from the top are excellent including a magnificent close up view of Glacier Peak. No water source on the trail, so bring plenty. Start by taking the Suiattle River trail from the large parking lot and after about 150 yards there will be a small sign on the left marking the Sulphur Mtn trail.
As you walk on the main trail adjacent to the Suiattle River, you will see a clearly marked sign and the trail head. The way it begins is how it is for a majority of the hike, steep. Expect nearly a hundred cut backs and be in a goat trailing mood. If you plan to camp, good luck, but if you're just going to hike it's wise to pack light. It's really rewarding to get near the top and start seeing those magnificent views, do yourself a favor and make sure it's on a clear beautiful day.