Vianen is a city and a former municipality in the central Netherlands, in the province of Utrecht. It is located south of the Lek River. Before 2002 it was part of the province of South Holland. Vianen is bordered by two major motorways leading to Utrecht: the A2 on its west, and the A27 just east of the town. Both roads can be notoriously congested near Vianen during peak commute hours.
The municipality was merged with the municipalities of Leerdam and Zederik on January 1, 2019. The name of the new municipality is Vijfheerenlanden which is a part of the province Utrecht.