 Burnt Fen is part of the South Level of the Fens, and as such was judged to have been drained satisfactorily as a result of the work of the Dutch drainage engineer Cornelius Vermuyden and his Adventurers in 1652.The courses of a number of rivers had been altered to improve drainage and reclaim land for agriculture, and a thanksgiving service was held in Ely Cathedral to celebrate the event.Burnt Fen was a low-lying region surrounded on three sides by the River Great Ouse, the River Little Ouse, and the River Lark.