Can a ham radio be traced?

Is it possible to trace the origin or location of a ham radio transmission? I've heard that ham radio operators communicate over the airwaves using frequencies that are not regulated by commercial services, but does that mean they're completely untraceable? Are there any methods or tools available for law enforcement or other authorities to pinpoint the exact location of a ham radio transmission, or is the anonymity of ham radio operators protected by the laws governing their activities?