This article discusses the State of California's efforts to deal with the problem of contraband cellphones in its correctional facilities. Intelligence gathering efforts by correctional administrators has found that inmates use contraband cellphones to plan drug transactions and communicate with other criminals outside of prison. These efforts also revealed that most contraband cellphones were came into the prisons by being thrown over the fence. The article discusses current efforts to prevent contraband cellphones from entering prisons such as improved lighting and the use of surveillance cameras, and the use of handheld cellphone detectors. The State is also working with the National Institute of Justice to find technology that performs more effectively in correctional facilities.