Windmill De Roos (The Rose) is located on the former city wall of Delft. The mill was built in 1679 on a roundel, a semi-circular defensive structure. A wooden post mill had already been standing on the same spot since 1500. This mill is the only remaining mill of the eighteen windmills in Delft.

Originally De Roos was also made of wood. In steps, it was converted into a brick one, which gave the mill a special shape. For instance, the substructure is hexagonal and the superstructure round. In 1728, the dwelling house was built in a semicircle around the mill. Around 1760, the mill looked as it does today.

The mill was in bad shape in the early 1980s. It was crooked due to a subsidence in 1929 and the cap was badly affected by a beetle. In 1988, the mill was refurbished and the superstructure straightened.

Windill De Roos is still used for grinding flour; since spring 2015 it is grinding organic grain for private individuals, bakers and the catering industry. The mill is turning a couple of days a week and can be visited.