Zwammerdam is a village in the Dutch province of South Holland along Oude Rijn river.

The name derives from a dam built in the Rhine river in 1165 AD by Count Floris III of Holland, to protect the land stream downwards from floods.

[4] Zwammerdam was a separate municipality until 1964, when it was divided between Alphen aan den Rijn and Bodegraven.

[6] In the 1970s during groundwork for the building of a new caregiving residence, remains were found of wooden ships from the Roman period.

[7] Extensive archeological excavations brought up six ships of different sizes, known as Schepen van Zwammerdam, now exhibited at the nearby open-air museum Archeon.