Nanocrystals, deposited on Si wafers, are maneuvered into sub-100-nm-sized pits or grooves by a Damascene process, that is, dropcasting and subsequent mechanical polishing. Single occupation is demonstrated for magnetic nanocrystals with diameter down to 18 nm. The figure show scanning electron microscopy and magnetic force microscopy images for a set of pits occupied by single Fe3O4 magnetic nanocrystals with 50-nm size.