The distribution of salinity, temperature and water transparency observed in the Miramichi estuary in 1950 and 1951 is correlated with the amount of precipitation, river discharge, wind velocity and other physical variables. Assuming complete mixing, the water exchange with the Gulf of St. Lawrence during a complete tidal cycle would be 15%. The residual or non-tidal circulation, resulting chiefly from river discharge, consists essentially of a seaward moving layer of drift within ten feet of the surface and a landward moving layer below that depth.