The Middle Fen and Mere Internal Drainage Board was originally constituted in 1757 and its District is located in the Cambridgeshire Fens, part of the South Level.
The District Boundary encloses an area of 8244ha. (20371ac.) with a total pumped catchment of 8954ha. (22126 ac.).
The District boundary is delineated by the River Lark to the east from the village of Isleham to Prickwillow. The District abuts the Padnal and Waterden District in the north. The western boundary is defined by the River Cam/Ely Ouse from Padney to Ely. In the south the District Boundary runs into the edge of the fen where there are greater areas of habitation at Wicken, Soham, Fordham and Isleham.
Soham Lode divides the Soham Mere section of the District from the old Middle Fen area.
The District has five pumped catchments which are pumped from five sites Henny (Soham Mere), Harrimere (Fordy area), Prickwillow (Soham Fen), Overfall (Middle Fen) and New Mill (Isleham Fen). The Prickwillow and New Mill systems are interlinked to provide greatest flexibility in pumping.
The District comprises of mainly high grade agricultural land much of which is below mean sea level and considerably below “flood level” and is therefore totally reliant on pumped drainage and flood defence for its existence as it has been for many years.