Conewango Creek is a 71-mile-long tributary of the Allegheny River in Pennsylvania and western New York in the United States. The creek's drainage covers much of southeastern Chautauqua County, New York, and western Cattaraugus County, New York. The creek's most notable tributary is the Chadakoin River, which supplies the creek water from …Conewango Creek is a 71-mile-long tributary of the Allegheny River in Pennsylvania and western New York in the United States. The creek's drainage covers much of southeastern Chautauqua County, New York, and western Cattaraugus County, New York. The creek's most notable tributary is the Chadakoin River, which supplies the creek water from Chautauqua Lake. The Chautauqua Ridge, a continental divide bounds the watershed to the north and west.