Lierde (Dutch pronunciation: [ˈliːrdə]) is a municipality located in the Flemish Ardennes, the hilly southern part of the Belgian province of East Flanders in the Denderstreek. The municipality comprises the towns of Deftinge, Hemelveerdegem, Sint-Maria-Lierde and Sint-Martens-Lierde. On January 1, 2006 Lierde had a total population of 6,399. The total area is 26.13 km² which gives a population density of 245 inhabitants per km². Lierde borders to Brakel, Zottegem, Herzele and Geraardsbergen. Lierde is known by the Ronde van vlaanderen, a bike race where cyclists climb all the hills of the flemisch ardennes.