The St. Regis River is fed by abundant water cascading from the northern Adirondack mountain slopes and dropping rapidly toward the St. Lawrence River, and its clean, cold water rushing over rocky streambeds and bedrock outcrops creates scenic beauty and sustains a healthy fishery. Native fish of the West Branch St. Regis include Brown Bullhead, Brown Trout, Brook Trout, Common Shiner, Creek Chub, Cutlip Minnow, Eastern Blacknose Dace, Fallfish, Fantail Darter, Golden Shiner, Longnose Dace, Northern Redbelly Dace, Pumpkinseed, Rock Bass, Smallmouth Bass, Walleye, White Sucker, and Yellow Perch, with Creek Chub, Longnose Dace, Rock Bass, Brook Trout, and Brown Trout most commonly caught. The source at St. Regis Pond is protected as part of the St. Regis Canoe Wilderness, and the river includes many falls and cascades, including Sylvan Falls about 7 miles upstream and 215 feet higher in elevation above Parishville. At Allen Falls the West Branch enters the Middle Branch to form the Greater St. Regis River at an elevation of 300 feet above sea level, then meanders 23.5 miles to its confluence with the St. Lawrence River in Canada, 3 miles north of Hogansburg, at an elevation of 155 feet above sea level. By the numbers, the total drainage area is 173,415 acres, or 271 square miles, the West Branch length is 70.5 miles, the total elevation drop is 1,285 feet, and mean water flow is 340 cubic feet per second. Approximately 1.2 billion years ago, North American and African crustal plates collided, uplifting great domes of rock and creating the ancient Adirondack Mountains, and after millions of years of uplift, erosion, and sedimentation, glaciers covering the metamorphic rock for thousands of years receded about 12,000 years ago, sculpting the mountains and streams that form the rivers of today.