Ridderkerk is a town and municipality in the western Netherlands, in the province of South Holland. The municipality had a population of 44,886 in 2010, and covers an area of 25.10 km² (of which 1.35 km² is covered by water). The municipality of Ridderkerk also includes the following towns, villages and townships: Bolnes, Oostendam, Rijsoord, Slikkerveer, and the hamlet Oude-Molen