Grand Marais in Seeland ou Pays des trois lacs is a region in Switzerland, at the foot of the first mountain range of the Jura Mountains contained by the three lakes of Morat (Murten), Neuchâtel and Bienne (Biel). Before the huge hydrological works Jura water correction, it was a marshland that covered . Before the correction the entire Grand Marais, along with the whole Seeland was prone to very severe recurring floods.