My uncle is a judge in the circuit court. This requires him to travel to diffferent locations to ensure wide visibility and understanding of cases within a region
That's cool!  What does a judge in the circuit court do?
He just has to travel a lot to make sure there is a wide visibility of the cases. Back in the days, the judges actually traveled on horseback! 
How large of an area does he have to travel?  Just within a single city, county, state or nation wide?
I believe it is within a broad area within a state. Most circuit courts have actually been replaced by judges that are regularly stationed.
Do you know who the first appointed circuit court judge was?
I'm not sure who the first was, but Abraham Lincoln was one such attorney who would ride the circuit!