AT A GLANCE
Why go?
Hennepin Island is a small, low island in the Mississippi River at the foot of St. Anthony Falls in downtown Minneapolis, wedged between Nicollet Island upstream and the roaring falls just below. Named for Father Louis Hennepin, the Franciscan missionary and explorer who first recorded the falls, it is far more famous as the scene of a near-disaster than as a place to stroll. In October 1869 the collapsed Eastman Tunnel chewed away much of the island and nearly dragged St. Anthony Falls downriver with it.↗↗
Today the island is dominated by active Xcel Energy hydropower works and engineered wasteways rather than open parkland, so the visitor experience happens at its edges. From the paths around St. Anthony Main, Water Power Park and the bridges that thread the falls, you can read a compact history of how Minneapolis harnessed, and nearly destroyed, the only major waterfall on the Mississippi River.↗↗
An Island That Almost Took the Falls With It
The story of Hennepin Island is the story of the Eastman Tunnel, one of the most dramatic engineering crises in American river history. In 1868–69 entrepreneurs William Eastman and John Merriam bored a passage under the riverbed, running from Nicollet Island beneath Hennepin Island and out below the falls, hoping to sell waterpower to mills upstream. On 5 October 1869 the rushing river punched through the thin limestone cap separating the tunnel from the channel, scouring the works, caving in parts of the island and triggering collapses that threatened to reduce the celebrated falls to a long stretch of rapids.
