Exploring Subway Cave and the Hat Creek Trail in Lassen National Forest

Subway Cave and the Hat Creek Trail are on opposite sides of Highway 89 in Lassen National Forest near Cave Campground. And their opposites in another sense: Subway Cave takes you deep underground in a dark, cool, and still lava tube, while the Hat Creek Trail takes you through the open air beside clear, tumbling waters, where you’ll always have sky above and trees, shrubs, and flowers trailside.

Hat Creek along the Hat Creek Trail in Lassen National Forest. The creek begins in Lassen Volcanic National Park. — Hat Creek

Subway Cave and the Hat Creek Trail Key Data

Length: 9.1 miles round-trip
Hiking time: 5 hours
High point: 4,350 feet
Total elevation gain: 500 feet
Difficulty: moderate
Season: early April through late November
Water: none; bring plenty
Map: USGS 7.5’ Old Station
Information: Hat Creek Ranger District, Lassen National Forest
Subway Cave Parking Area GPS coordinates: N 40 41.126 W 121 25.141
Notes: dogs prohibited in Subway Cave, but allowed on Hat Creek Trail; toilets at the Subway Cave parking area, and in Cave Campground and Bridge Campground

Best Day Hiking Trails in Upper California

My compact guidebook has the 125 best day hikes:

Mount Shasta and nearby
Lassen Volcanic National Park
Trinity Alps and Marble Mountains
Redding area
Whiskeytown and Shasta Lakes

Includes trailhead directions and detailed maps and trail descriptions

Buy it: on Amazon | on Bookshop.org
Often available at bookstores and outdoor stores (call first!)

Driving Directions to the Hat Creek Trail and Subway Cave Trailhead

To start your explorations, take the Subway Cave access road on the east side of Highway 89, across the road from Cave Campground and 0.3 mile north of the junctions of Highways 89 and 44 East.

Trail map of the Hat Creek Trail, including Subway Cave, Cave Campground, and the Pacific Crest Trail in Lassen National Forest — Trail map of the Hat Creek Trail, including Subway Cave and Cave Campground. (Courtesy of Caltopo.com)

Exploring Subway Cave

It’s always cool in Subway Cave, so bring a sweater and two flashlights per person. Also follow any posted regulations at the entrance to Subway Cave.

Entrance to Subway Cave, a lava tube in Lassen National Forest — Entrance to Subway Cave

Subway Cave, a 1,300-foot-long lava tube, formed around 30,000 years ago. Vast eruptions of fluid basalt flowed northward through the Hat Creek Valley. Lava closest to the surface cooled more rapidly than the lava below, allowing the hotter lava to move farther before solidifying, leaving the cave as an empty space behind it.

Lighted information signs discuss the cave’s natural history and explain the formation of such colorfully named features as Stubtoe Hall and Lucifers Cul-de-Sac. Several parts of the tunnel are completely dark though, so you’ll be glad you brought the flashlights. When you emerge into daylight on the far side you have two options: Return through the cave or take the path back to the parking area.

Inside Subway Cave in Lassen National Forest — Inside Subway Cave

Hiking the Hat Creek Trail

Hat Creek viewed from the Hat Creek Trail footbridge near Cave Campground in Lassen National Forest — Hat Creek from the bridge near Cave Campground

To do the Hat Creek Trail (5E27), head across Highway 89 to the northwest side of Cave Campground, where a wooden footbridge spans the stream near a 5-foot waterfall. Cross over, turn right, and soon reach a massive sugar pine and its foot-long cones. Continue the mostly level stroll through vegetation that varies from open chaparral dominated by greenleaf manzanita to an open forest of incense cedar, ponderosa and Jeffrey pines, and white firs. Alders and willows flourish in the wet environs near the creek’s banks.

Look for a small waterfall just beyond a bridge at 0.6 mile, and occasionally look behind you for tree-framed views of Lassen Peak in Lassen Volcanic National Park. You’ll also enjoy views of many other Cascade notables, including Mount Shasta, Burney Mountain, Crater Peak, Magee Peak, and Freaner Peak. The mountain to your immediate left is Sugarloaf Peak; its basalt talus often borders the trail.

Find two more small waterfalls at 2.2 and 2.4 miles as you and Hat Creek drop gently into a canyon. Reach another bridge at 3.7 miles, and finally reach the end of the path at 4.3 miles at Bridge Campground (3.6 miles north of Cave Campground if you’re arranging a car shuttle).

Hat Creek Trail Video

Here’s my Youtube video that I shot from the bridge in Cave Campground. Subscribe to my Northern California Hiking Trails Youtube channel and see dozens more similar videos.