Head of tide
![Cromwell Weir marks the tidal limit of the River Trent, a major river in England[1]](/Images/godic/202502/16/Geograph_-_2561867_-_by-Jonathan-Thacker4301.jpg")
Head of tide or tidal limit is the farthest point upstream where a river is affected by tidal fluctuations, or where the fluctuations are less than a certain amount. This applies to rivers which flow into tidal bodies such as oceans, bays and deltas.