The Haven is the tidal river of the port of Boston, Lincolnshire in England. It provides access for shipping between Boston Deeps in The Wash and the town, particularly, the dock. It also serves as the outfall into the sea, of the River Witham and of several major land drains of the northern Fens of eastern England, which are known collectively as the Witham Navigable Drains. (TF 337 426).