Aalst is a ceety an municipality on the Dender River, 19 mile northwast frae Brussels. It is locatit in the Flemish province o East Flanders in the Denderstreek. The municipality comprises the ceety o Aalst itsel an the touns o Baardegem, Erembodegem, Gijzegem, Herdersem, Hofstade, Meldert, Moorsel, an Nieuwerkerken.