A method and apparatus for geofencing mobile transmissions. The method includes determining a geographic location of a mobile transmitter. Then, a geographic interference contour of the mobile transmitter is determined. The mobile transmitter is operating over a specific frequency at the geographic location. A neighboring service contour is then determined. The neighboring service contour is associated with an FCC license that allows transmissions over a specific channel that includes the specific frequency. The interference geographic contour and the service contour are compared to determine if there is overlapping. Thereafter, transmissions from the mobile transmitter are controlled in order to comply with FCC regulations.