Grand canonical Monte Carlo simulations are employed to investigate the structure of water adsorbed on kaolinite surfaces with trenchlike defects. The results obtained for two water models (SPC/E and TIP5P-E) at 235 K are essentially the same. Calculation of water density profiles in all three dimensions shows that a dense ordered state is present in our trench systems. The narrowest trenches have the highest water density and display clearly layered structures along the width and depth of a trench. The water within a trench shows distinct proton order and is strongly ferroelectric. These ordered structures might be important in the initial stages of nucleation and growth of ice on kaolinite surfaces.