Numansdorp is a village and former municipality in the province South Holland in the Netherlands and is located on the island Hoeksche Waard near the Hollands Diep. On 1 January 1984, the municipalities Numansdorp and Klaaswaal were merged into one municipality called Cromstrijen. Cromstrijen was merged into the new municipality Hoeksche Waard in January 2019.
In 1793 an earthen fort was built next to the harbour of Numansdorp, called Fort Buitensluis. The purpose of this fort was to keep an eye on the shipping between the Volkerak and Hollands Diep. In the same year, France attacked the Austrian Netherlands. Thanks to the Battle of Neerwinden the Austrian Netherlands remain in Austrian hands. In 1795 the Batavian Republic starts. In 1862, the second cabinet of Thorbecke, ordered to reinforce the fort. From 1874 on, the fort became a part of the Defence line of the Hollands Diep and the Volkerak. In 1915 the fort was reinforced for a second time, this time with reinforced concrete.
Numansdorp has a population of over 8,716 people.