Year: 1.1 billion years ago
The Mohawk River is the main tributary of the Hudson River. Rising in north central New York, the Mohawk flows straight east to its confluence with the Hudson right near Albany. This makes the 149 mile long river a critical part of the State's infrastructure.
The river is over one billion years old, but until 12,000 years ago it was a small stream. When the Laurentian Glacier retreated at the end of the last Ice Age, its major outflow was through the Mohawk Valley, turning the watercourse from a creek to a large river.
It gets its name from the Mohawk tribe, and demarcated the southern boundary of their homeland. The river and its valley separate the Catskill Mountains from the Adirondack Mountains.
From the earliest times, the Mohawk River was a major river road, allowing people to cross the Appalachian Mountains with ease. As the only such river road in the northeast, the Mohawk was central to New York's early development and to general westward expansion. Many future Buckeyes and Hoosiers used the river to pass through the mountains in order to settle Ohio and Indiana.
With the completion of the Erie Canal in 1823, the Mohawk River became the main artery for Midwestern products to travel from the Great Lakes to the Atlantic Ocean. Suddenly, farmers in distant Minnesota could sell their crops to European buyers. New York City boomed as the great seaport at the end of this vast internal waterway --- largely because the Mohawk River is where it is.
Many of New York's "Rust Belt" towns --- Schenectady, Utica, and Rome among them --- grew up along the river, and the New York State Thruway parallels the river for much of its length.
It remains important today, as the main natural stretch of the New York State Barge Canal System, the successor to the Erie Canal.