The distribution of spawning blueback herring was determined on the West Branch of Cooper River and on the Santee River, South Carolina. On the West Branch of Cooper River, the main river channel and abandoned ricefields were utilized for spawning. The use of tributaries for spawning was limited. On the Santee River, the main river channel and tributaries were utilized for spawning. Ranges for selected physical and chemical water quality characteristics associated with the distribution of spawning blueback herring were determined from 9 Cooper River and 15 Santee River sampling stations during the herring run. Those ranges were: surface water temperature, 11 - 20 C; dissolved oxygen, 6 - 11 mg/l; dissolved carbon dioxide, 5 - 25 mg/l; pH, 6.0 - 7.5; and depth, 0.4 - 3.1 m.