Carbon nanotube adhesion force measurements were performed on single-walled nanotubes grown over lithographically defined trenches. An applied vertical force from an atomic force microscope (AFM), in force distance mode, caused the tubes to slip across the 250-nm-wide silicon dioxide trench tops at an axial tension of 8 nN. The nanotubes slipped at an axial tension of 10 nN after being selectively coated with a silicon dioxide layer.