Rijnwoude was a municipality in the western Netherlands, in the province of South Holland. The municipality covered an area of 57.89 km2 of which 1.20 km2 was water. Rijnwoude was formed in 1991 as Rijneveld through the merger of the former municipalities of Benthuizen, Hazerswoude and Koudekerk aan den Rijn. In 1993 the municipality was renamed to Rijnwoude. In 2014 the municipality was dissolved and its land area was amalgamated into Alphen aan den Rijn. The municipality of Rijnwoude consisted of the communities Benthorn, Benthuizen, Hazerswoude-Dorp, Groenendijk, Hazerswoude-Rijndijk (location of town hall), Hogeveen, and Koudekerk aan den Rijn.