Melsen is a village in the province of East Flanders, Belgium, and is a part of the municipality of Merelbeke. It covers an area of roughly 3 square kilometers. Its terrain is largely made up of one great hill. The northern and southern slopes of the hill, which are fairly steep for the surrounding area, form the natural boundaries with the bordering villages of Vurste and Schelderode. The eastern slopes of the hill evolve into agricultural land and farther east into the forest of Makkegem. The western slope descends into a marsh that is connected to the Schelde (Scheldt) river.