Willemstad is a city in the Dutch province of North Brabant. It is located in the municipality of Moerdijk. Its population as of 2021 was 2,490.Willemstad is a small historical town with well preserved fortifications. It lies on the Hollands Diep, close to the Haringvliet and Volkerak. It received city rights in 1585. The Reformed Church was built in 1607 as the first new Protestant church building in the Netherlands.