Great Falls (Passaic River)

The Great Falls of the Passaic River is a prominent waterfall, 77ft high, on the Passaic River in the city of Paterson in Passaic County, New Jersey, United States. The falls and surrounding area are protected as part of the Paterson Great Falls National Historical Park, administered by the National Park Service. The Congress authorized its establishment in 2009.One of the United States' largest waterfalls, it played a significant role in the early industrial development of New Jersey starting in the earliest days of the nation. It is part of the Great Falls of Paterson-Garret Mountain National Natural Landmark. It has also been designated as a National Historic Landmark District since 1976. The Great Falls' raceway and power systems were designated an Historic Civil Engineering Landmark in 1977.HistoryFormation and early historyGeologically, the falls were formed at the end of the last ice age approximately 13,000 years ago. Formerly the Passaic had followed a shorter course through the Watchung Mountains near present-day Summit. As the glacier receded, the river's previous course was blocked by a newly formed moraine. A large lake, called Glacial Lake Passaic, formed behind the Watchungs. As the ice receded, the river found a new circuitous route around the north end of the Watchungs, carving the spectacular falls through the underlying basalt, which was formed approximately 200 million years ago.