Susanville is a city and county seat of Lassen County, California, USA. At the 2000 census, the population was 13,541. Susanville, a former logging and mining town, is the site of the High Desert State Prison. The prison, a high-security facility, opened in 1995. The prison and its effects on the community was featured on the PBS documentary P.O.V.. Susanville apartments for rent comparison page shows most up to date rent information on Susanville apartments and houses. Rent information is obtained from multiple rental sources but we cannot guarantee their accuracy.