Rising just east of Sisson's Farm near Crowland it flows very roughly eastwards, following the general line of the River Welland but a little to the south.

The current land usage, and the rights of the drainage authorities to flood it can be traced back at least to the Crowland Inclosure Act 1801 (41 Geo.

Cowbit Wash was flooded annually to protect Spalding until the creation of the Coronation Channel allowed excess water to bypass the town.

It is this bank that restrains the spreading floodwaters: the New River lies in the bottom of this basin to remove the waters.

The availability of a suitable geological feature on which to build this bank determined the shape of the washes, and its location can be traced back through antiquity.