Combined scanning force and friction force microscopy (FFM) operated under ambient conditions as well as in inert gas atmosphere has been applied to investigate the topographical structure of the domain boundary on the triglycine sulfate (010) surface. The inspection of freshly cleaved (010) surfaces revealed the coexistence of a topographical step (height ≈ b/4) with the domain boundary. When the boundary is moving due to, e.g., heat treatment of the sample the topographical step changes its position according to the domain boundary motion. Additionally, opposite cleavage faces exhibit a mismatch of the topographical steps at the domain boundaries when the crystal is cleaved under ambient conditions. This mismatch does not occur when the crystal is cleaved in a water-free atmosphere. A model is presented which explains these observations.