Richardson County is the easternmost county in the U.S. state of Nebraska. As of the 2020 census, the population was 7,871. Its county seat is Falls City. In the Nebraska license plate system, Richardson County is represented by the prefix 19. Parts of the Ioway Reservation and the Sac and Fox Reservation are located in the southeast corner of the county between Falls City, Rulo, and Hiawatha. The incorporated village of Preston, Nebraska is located inside the latter reservation.