Sheriff's Department

Bill Cassell

Petroleum County Sheriff – Bill Cassell
P: (406) 429-6551

Sheriff Bill Cassell has worked for Petroleum County Sheriff’s Office Since May of 2007. He started his Law Enforcement career in the US Navy as a Military Policeman in May of 2002. Bill attended and graduated from Montana Law Enforcement Academy in March of 2008 and became POST certified in August of the same year. Along with his duties as Sheriff, Bill is also the Petroleum County Manager and Disaster and Emergency Services (DES) Coordinator.


Registered Sex/Violent Offenders: We currently have none registered in Petroleum County.

Concealed Weapons Permits: Applications are available at the Petroleum County Sheriff’s Office.

Petroleum County Search and Rescue: Petroleum County Search and Rescue is primarily made up of volunteers. There are currently 12 members in the department which is led by Sheriff Cassell. The unit is capable of performing rescues in almost any situation from high angle rope rescue to searching for lost hunters in the rugged terrain of the Missouri Breaks in northern Petroleum County. If you are interested in volunteering please call 406-429-6551.