It al depends on where you are in the states. Some Sheriff Dept's have a SAR helicopter, and the California Highway Patrol has a bunch as well. Plenty of police departments have them- it is generally very localized, however, the National Guard gets plenty of work too, I am sure.
Example:
Sonoma County Sheriff Rescue Helicopter - Bell 407
I don't know why the winch is missing from that picture- but they do vertical reference rescues with their winch.