Lightning overvoltages coming from overhead lines, such as power distribution lines, telecommunication lines, and antennas to residences have been actively studied. However, the relation between a lightning strike to the ground and overvoltages in residences remains unclear. This paper proposes a simulation model to estimate lightning overvoltages caused by ground potential rise due to the lightning strike to the ground. The proposed model is derived on the basis of the Thevenin theorem, and can be realized in the Electromagnetic Transients Program.