De Molen van Piet (or officially “De Groot”) is located in the city centre of Alkmaar on the top of the former rampart, towering above the surrounding urban development.

This windmill with a stage was built in 1769 and from then on served as a corn mill for ages. In the year of 1874 the mill is owned by miller S. de Groot. Ten years later mill "De Groot" is bought by C. Piet, who came from Aalsmeer and was a miller in Sloten. He had a house made at the lower floors of the mill. The mill's surname remained popularly associated with the mill and the old name “De Groot” is hardly used. Nowadays the fourth generation of the Piet family still lives in the mill.

The mill is now owned by the municipality, but is still inhabited and milled - every now and then - by a member of the Piet family. Only during special occasions the mill can be visited.