The Genesee River is notable for its unusual northward flow across New York State. This river begins its 157-mile journey in the Allegheny Plateau, spanning northern Pennsylvania and southwestern New York. The river’s course takes it through a diverse landscape, from remote, forested hills to the urban center of Rochester. Its distinctive path and geological features are a result of the massive glacial events that shaped the entire Great Lakes region.
The River’s Final Destination: Lake Ontario
The Genesee River drains into Lake Ontario, one of North America’s Great Lakes, providing a direct connection to the greater St. Lawrence River system. It empties into the lake at the Port of Rochester, flowing specifically into the Rochester Embayment, a broad bay on the lake’s southern shore. This final stretch of the river is part of the Lake Ontario watershed.
The river mouth at Rochester’s Charlotte neighborhood is a significant geographical point, once a busy industrial port that now caters primarily to pleasure craft and ferry service to Canada. The river drains an area of approximately 2,500 square miles across parts of ten counties in both New York and Pennsylvania. The elevation drop from the river’s source to its mouth is dramatic, falling from about 2,275 feet to just 243 feet above sea level.
The discharge has historically been used to generate hydroelectric power in the Rochester area, a practice that continues today. The river also supports recreational activities like fishing and paddling near the lakefront.
Tracing the Path: From Headwaters to the Great Lakes
The headwaters of the Genesee River are located in the Allegheny Hills near the village of Ulysses in Potter County, Pennsylvania. From this elevated starting point, the river flows nearly 160 miles in a consistent northward direction, a flow pattern uncommon for the region. The river’s initial course is characterized by a steep stream slope as it descends from the plateau.
As the river crosses the New York state line, it enters a region dominated by extensive agricultural development and mixed forest. It passes through several counties, including Allegany, Livingston, and Wyoming, where the landscape consists of gently rolling hills and valleys. The river’s valley was deepened and widened by glacial action during the last Ice Age, leaving behind fertile soil deposits that support productive farmland.
Near Rochester, the river enters the Lake Ontario Lowlands, where the stream slope significantly flattens before its final descent through a series of gorges and waterfalls. This northward flow is a direct result of the geological history of the region.
Defining Features: Gorges and Waterfalls
The Genesee River is known for the deep gorges and numerous waterfalls it has carved. The most spectacular section is found in Letchworth State Park, often called the “Grand Canyon of the East,” where the river has cut a 17-mile gorge with cliffs reaching up to 600 feet high. Within this gorge, there are three major cascades known as the Upper, Middle, and Lower Falls.
The Middle Falls is the highest of the three, while the Upper Falls is notable for the massive railway bridge that spans the gorge immediately above it. These features were formed as the river eroded through Devonian-age bedrock, mostly shales, siltstones, and sandstones, following the retreat of the last glaciers. The river’s power is harnessed nearby by the Mount Morris Dam, a large flood control structure that protects downstream communities.
Farther north, within the city of Rochester, the river descends over another series of waterfalls, including the High Falls, Middle Falls, and Lower Falls. These urban cascades, which cut through Silurian-age limestones and shales, were historically the power source that established Rochester as the “Flour City” in the 19th century.