and locations of nuclear reactors, 2008
The Nuclear Regulatory Commission has divided the US territory into four regions:
These four regions oversee the operation of 104 power-producing reactors, and 36 non-power-producing reactors. This oversight is done on several levels, for example:
- Each power-producing reactor site has Resident Inspectors, who monitor day to day operations
- Numerous special inspection teams, with many different specialties, routinely conduct inspections at each site
- Whistleblower reports are investigated by the Office of Enforcement, specifically the Allegations branch 
The NRC previously had five regions. In the late 1990s, the Region V office in Walnut Creek, California was absorbed into Region IV and Region V was dissolved.