Stumphouse Mountain Tunnel
An unfinished pre-Civil War railroad tunnel carved by hand into the granite of Stumphouse Mountain, about six miles north of Walhalla on SC-28 — the southern leg of the Moonshiner 28 route. Workers using hand tools before the war completed only 1,600 of a planned 5,600 feet before funding collapsed in 1859. The tunnel today maintains a constant 50°F interior temperature year-round with 85% humidity; the city of Walhalla operates it as the centerpiece of Stumphouse Park, which also includes the adjacent Issaqueena Falls, a mountain bike park, and the Palmetto Trail's Stumphouse Passage. About a quarter mile of the tunnel is open to walk. Admission is $5 per vehicle; open daily 10 a.m.–5 p.m. except Christmas.
What you're stepping into is a project that ran out of money before the Civil War started and never resumed. Workers — primarily Irish immigrants — hand-drilled through solid blue granite beginning in the 1850s, using sledge hammers, hand drills, and black powder. At the mountain's hardest stretches they could advance only about 200 feet per month. By 1859, South Carolina's legislature cut funding, and the tunnel was left at roughly 1,600 feet of a planned 5,800-plus-foot bore — a dead-end into the rock that you can still walk today. The opening is listed on the National Register of Historic Places, and the tunnel sits within Stumphouse Park, operated by the city of Walhalla.
The cold is the first thing that registers when you cross the threshold. The interior holds a constant 50°F with 85% humidity year-round — useful enough that Clemson University used it for decades to cure blue cheese, until the process was eventually moved to a climate-controlled facility where those same conditions were replicated. Bring a flashlight; there is no overhead lighting, and the far end of the roughly quarter-mile walk-in approaches total darkness. The tunnel runs damp, and standing water is common.
Issaqueena Falls is within the same park — a short walk or a quick repositioning of the bike to the separate parking area. The $5-per-vehicle entry covers both. The park is open daily except Christmas, and the trail to the falls observation deck is an easy quarter-mile walk on its own.
A genuinely strange stop on the Moonshiner 28 run — walk into a 50°F hand-drilled Civil War-era tunnel on a hot summer day, then cool off further at Issaqueena Falls just steps away. Worth the $5 entry and the short detour off SC-28.
Shot by the riders who've run it.
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