Dirttrails
GNCCs are hare scrambles. They’re just call Grand National Cross Country races.
The idea is to race as fast as you can around a loop of trail set up in the woods.
The length of the loop and the number of laps will vary and depend on the race and the class you ride in.
The better ( faster ) riders might do 7 laps of a 6 mile loop where a slower /newer “C” rider race might only last for 4 laps of the same loop.
Unlike an enduro you do not have to keep to a predetermined time schedule, the idea is the fastest rider to complete all required laps and cross the finish line first wins.
Hare n Hound races are different - not always raced in a number of laps around one loop. I believe they are usually one long race from point A to point B and are 100 miles or so.
Follow this link to the AMA and look under the various types of racing – if you look around there are rules listed for each type of racing. You should be able to find what you are looking for.
AMA < --- click
But I suggest you look into contacting a local club for information on races in your area.