Lake Yankton Located just below Gavin’s Point Dam; partly in Yankton, South Dakota. A relatively small reservoir below the spillway at Gavin’s Point Dam that offers good birding along its wooded shoreline and gulls, terns and waterfowl during migration. Get Directions For Driving Walking Bicycling show options hide options Avoid Tolls Avoid Highways From To Fetching directions...... Reset directions Print directions