The Tar Tunnel is located on the north bank of the River Severn in the Ironbridge Gorge at Coalport, England, and now forms part of the Ironbridge Gorge Museum Trust.
Miners struck a gushing spring of natural bitumen, a black treacle-like substance, when digging a canal tunnel for the Coalport Canal in 1787. It was a great curiosity in the 18th century and bitumen still oozes from the wall today. Its chief commercial use at the time was to treat and weatherproof ropes and caulk wooden ships, but small amounts were processed and bottled as a remedy for rheumatism.
The plan to cross the hill was abandoned and the Hay Inclined Plane was built instead, its base being alongside the canal basin.