The Nebraska State Penitentiary (NSP) is a state correctional facility for the Nebraska Department of Correctional Services. Located in Lincoln, it is the oldest state correctional facility in Nebraska, opening in 1869. Until after World War I, it was the only adult correctional facility in the state. During 1980-1981, the existing cellblocks constructed during the second half of the 19th century were replaced by four (later five) modular housing units.