Donner Pass Summit Tunnels

The Donner Pass Summit Tunnels are a series of abandoned railroad tunnels from the original Central Pacific transcontinental railroad, drilled through the granite ridge above Donner Lake in the 1860s. They are now accessible for hiking and exploring — you can walk through the original Summit Tunnel, a dark bore through granite with occasional shafts of light from ventilation openings, and emerge on the other side of the ridge with views in both directions.

The site is reached by a moderate hike from the Pacific Crest Trail trailhead off Donner Pass Road. The tunnels are unrestricted and unlit — bring a headlamp. The old Central Pacific roadbed above the tunnels is also walkable and gives a sense of the engineering achievement required to push a railroad across the Sierra Nevada. The modern I-80 freeway cuts through the same pass below, but the old road is quieter and more historically resonant.

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A story
The Summit Tunnel — Tunnel 6 — was hand-drilled through 1,659 feet of solid granite by Chinese workers who lowered themselves down the cliff face in wicker baskets to drill explosive charges. During the brutal winter of 1866–67, the workers lived in snow tunnels beneath 40 feet of Sierra Nevada snowpack, working around the clock to advance the line. When it was finished, it was the longest railroad tunnel in the United States.