Many electronic devices, like non-volatile high-density memories, ultra-fast switches, and thin film capacitors, rely on ferroelectric materials—a class of materials with spontaneous electrical polarization which can be reproducibly switched. In two-dimensional (2D) and quasi-2D ferroelectric materials the size of ferroelectric domains can be small which may enable the miniaturization of devices. Understanding of ferroelectric domain structure at the atomic scale is, however, limited, hindering the development of functional device units at the microscopic level.