| Oatka Creek Allan's Creek | |
|---|---|
 Oatka Creek in Wheatland | |
 Genesee River map showing Oatka on upper left | |
| Etymology | "Leaving the highlands" in Seneca |
| Location | |
| Country | United States |
| State | New York |
| Region | Western New York |
| Counties | Wyoming, Genesee, Monroe |
| Towns | Gainesville, Warsaw, Middlebury, Covington, Pavilion, Stafford, Le Roy, Wheatland |
| Physical characteristics | |
| Source | |
| • location | Near Gainesville-Warsaw town line |
| • coordinates | 42°41′42″N 78°5′38″W / 42.69500°N 78.09389°W |
| • elevation | 1,380 ft (420 m) |
| Mouth | Genesee River |
• location | 1 mi (1.6 km) east of Scottsville |
• coordinates | 43°1′26″N 77°43′28″W / 43.02389°N 77.72444°W |
• elevation | 500 ft (150 m) |
| Length | 58 mi (93 km) |
| Basin size | 215 sq mi (560 km2) |
| Discharge | |
| • location | Garbutt |
| • average | 215.3 cu ft/s (6.10 m3/s) |
| • minimum | 0.9 cu ft/s (0.025 m3/s) (August 1, 1965) |
| • maximum | 7,050 cu ft/s (200 m3/s) (March 31, 1960) |
| Discharge | |
| • location | Warsaw |
| • average | 67 cu ft/s (1.9 m3/s) |
| • maximum | 4,110 cu ft/s (116 m3/s) |
| Basin features | |
| Tributaries | |
| • left | Cotton Creek, Relyea Creek, Stony Creek |
| • right | Mud Creek |
Oatka Creek (/oʊˈætkə/ oh-AT-kə) is the third longest tributary of the Genesee River, located entirely in the Western New York region of the U.S. state of New York. From southern Wyoming County, it flows 58 miles (93 km) to the Genesee near Scottsville, draining an area of 215 square miles (560 km2) that includes all or part of 23 towns and villages in Wyoming, Genesee, Livingston and Monroe counties as well. Its name means "leaving the highlands" or "approaching an opening" in Seneca.
Like its parent stream it originated during the end of the last Ice Age, as glacial impact on the upper Allegheny Plateau created a rolling landscape streams could gradually erode through, The Oatka carved a deep groove known today as the Oatka Valley, where the upper creek's two major settlements would be established. Native Americans of the Seneca nation established a few settlements along it where clearings arose in the forest. The Revolutionary War's Sullivan Expedition brought the valley's fertile soil to the attention of the emerging nation, and the region was opened for settlement shortly after the war.
For a time the Oatka was called Allan's Creek after the area's first settler, Ebenezer "Indian" Allan. Its waterpower facilitated early 19th-century European settlement of the abundant fertile lands in the Holland Purchase. Today it remains an important regional resource, used for water supply and recreational purposes, and actively protected to assure water quality. It is a popular trout stream, stocked from the oldest fish hatchery in the Western Hemisphere near its mouth. A dam in Le Roy makes the section below it a losing stream, dry during the warm months of the year as the stream flows through subterranean channels.