Bellingham’s neighborhoods have their own character, but some share a feature you can’t even see: a wide network of underground coal mine tunnels.

Hundreds of miles of abandoned coal passageways honeycomb Bellingham’s depths, none bigger than the massive Bellingham Coal Mine beneath the Birchwood and Columbia neighborhoods. The mine, which operated from 1918–1955, was the last to close, ending an era that began with coal’s discovery here in the early 1850s.

Still, the tunnels are part of Bellingham lore. Bellingham’s coal mine era featured about a dozen mines, including several near Lake Whatcom and one directly beneath the heart of downtown. In 1997, an abandoned coal tunnel, just 88 feet below ground level, was discovered near the corner of Railroad and Holly, where the Starbucks and office building now stand. The city had hired an engineering firm to do exploratory drilling — maps detailing the location of the mine, owned long ago by a California firm, had burned up in San Francisco’s Great Fire, said engineering geologist Dan McShane.

As for underneath Birchwood and Columbia, the mine’s depth ranges from 300 to 1,100 feet through 11 levels of tunnels, the shallowest near the mine’s sloping entrance. No trace of the entrance remains, paved over by a shopping center where the shuttered Albertson’s supermarket at 1650 Birchwood Ave. is located. Ventilation shafts have been sealed and experts believe the tunnels have compacted over the years, says Whatcom Museum photo archivist Jeff Jewell, with few instances of sinkholes or major settling reported on the surface. Yet McShane calls it “fortuitous” that the Bellingham Country Club’s golf course was built instead of houses — he suspects the course stretches over ground less stable than that in the surrounding neighborhood.

Still, neighborhood residents have blamed the mine for everything from sandy backyard soil to potholes, and some worry how much worse an earthquake would be to a neighborhood with an abandoned mine under it.

Jewell, a Columbia neighborhood resident himself, says the Bellingham Coal Mine’s football-field-depth is a buffer to residents worried a sinkhole will someday swallow their car or house. But the mine’s unsettling existence lingers. Sometimes, when the housing market booms in Bellingham, realtors regularly bring jittery clients to Jewell’s office to pore over the mine’s massive blue map. It’s hard to forget what lurks beneath. Residents just hope it’s far enough.