This paper studied the effects of an adjacent inclined rock face on the at-rest earth pressure acting on a rigid retaining wall. Horizontal earth pressures in loose (Dr = 35%) and compacted (Dr = 72%) dry Ottawa sand were measured. A steel interface plate with inclination angles 0o, 45o, 60o, 70o, and 80o were used to simulate the inclined rock face. The measured distribution of earth pressure was not linearly with depth, and was mostly lower than Jaky's solution. As the rock face inclination angle increased, the magnitude of at-rest soil thrust decreased, and the total thrust rose to a higher location. With the inclination angle of 80o, only a small amount of sand was filled in the narrow gap between the wall and the inclined interface. The vertical stress in the soil slice was partially resisted by the friction on the nearby inclined rock face. With decreasing vertical stress in the soil mass, the horizontal stress acting on the wall decreased.