Onderdendam is a village in Het Hogeland municipality in the province of Groningen, the Netherlands.

Even though it seemingly translates to "below the dam", the etymology is unclear.

[3] Onderdendam developed in the 16th and 17th century at the intersection of land- and waterways.

In 1653, the Boterdiep was built which further enhanced its position, and it became a village of warehouses and traders.

[4] The court house was built in 1804 as a wide white plastered building on the main street.