The State and Federal cooperative program for the systematic collection of stream-flow records in Iowa was initiated in L914, although a few records were obtained by special arrangements during an earlier period. Since the beginning of the cooperative program measurements of stage or discharge have been obtained at about 100 stations on Iowa streams and lakes for periods of various lengths. The longest records are those for the Missis sippi River at Le Claire and Keokuk where authenticated data have been used to extend the record back to 1873 with decreasing accuracy for the earlier years. In addition to the records of daily stages or discharges, hundreds of measurements of a mis cellaneous character also have been made at other points.