Entry No. 61 — the Seattle file — filed under: ruins
Ford Slope Mine
Opened in 1905, the Ford Slope Mine was once the largest and most productive coal mine on Cougar Mountain, plunging down five levels to a depth of 1,500 feet. The operation abruptly ended in 1929 after a devastating fire destroyed the nearby Coal Creek bunkers. Today, the mine's arched concrete entry remains visible along the trail, permanently sealed with concrete and preserved as an outdoor historical exhibit.
The story
In 1905, crews on Cougar Mountain began driving an inclined shaft into the earth that would become the largest and most productive coal operation in the Newcastle district: the Ford Slope Mine. Over twenty-four years of continuous digging, miners carved out five distinct subterranean levels, following the coal seam straight down to a depth of 1,500 feet.
The operation came to a sudden, permanent halt in 1929—not because the coal ran out, but because a fire burned the nearby Coal Creek coal bunkers to the ground. With the surface infrastructure turned to ash and the coal market slumping, the mine was abandoned. To keep the curious from falling down a 1,500-foot hole, workers poured a solid wall of concrete directly into the arched entryway.
Today, that sealed portal sits right alongside the forest trail like an industrial tomb, framed by a short run of iron track and an authentic mine cart sitting out front. Historical displays detail the vanished boomtown around you, but the real draw is standing inches from a concrete wall that permanently caps a quarter-mile of dead, pitch-black subterranean shaft.
What it's like
Getting to the portal is simple: a level, half-mile round-trip walk along the flat Rainbow Town Trail inside Cougar Mountain Regional Wildland Park, though you can easily hook into miles of connected forest trails. At the site, you'll find the sealed concrete archway, the vintage mine cart on rails, and interpretive panels detailing the early 1900s mining operation. Because it is so close to Seattle, the trail gets crowded on sunny weekend afternoons; hit it early on a foggy weekday if you want to inspect the portal without waiting for hiking groups to clear the frame.
The move: Hike the scenic Rainbow Town Trail in Cougar Mountain Regional Wildland Park to view the sealed concrete mine portal, read the historical interpretive displays, and enjoy a picnic nearby.
📍 Before you go The mine is located within Cougar Mountain Regional Wildland Park and is legally accessible via public hiking trails, but the mine entrance itself is permanently sealed with concrete for safety and cannot be entered.
- 📍 Bellevue
- 💸 Free
- ⚡ Low-key
- 🌗 Outdoors
Where: Rainbow Town Trail, Bellevue, WA 98006, USA
Hours: Added 2026-07-20 — confirm current access before you go.
Pair it with
- Abandoned Clay Pit — Stay inside Cougar Mountain Regional Wildland Park to check out another massive industrial scar left behind by mid-century resource extraction.
- Dairy Barn Ruins — Head west to Mercer Island to trade Cougar Mountain's sealed coal entry for the concrete foundations of an old institutional dairy barn.
- Bill Speidel's Underground Tour — Pair Bellevue's sealed deep-coal portal with a subterranean walk through Pioneer Square's buried 1880s storefronts.
Good to know
Can you go inside the mine shaft?
No. The arched entrance is permanently sealed solid with concrete for safety, so you can only view the exterior entry, rails, and historical exhibit.
How difficult is the hike to the mine?
It is a short, easy walk. The direct route along the Rainbow Town Trail is a level-to-gentle half-mile round trip.
Why did the mine shut down in 1929?
A devastating fire destroyed the nearby Coal Creek coal bunkers, wiping out the surface infrastructure required to store and process the mine's output.
Where is the mine located?
It is located along the Rainbow Town Trail within Cougar Mountain Regional Wildland Park in Bellevue, Washington.
Plan a visit & invite your people →
Further reading: eastsideheritagecenter.org · trailcooking.com · seattletimes.com · wta.org · Reddit
last checked: 2026-07-20