Road races are often held on large loop courses. The one I raced in yesterday was on a 23 mile loop. Some categories did two laps, the higher category or younger fields did three.

Point to point road races like they have in the Tour de France are rare. The logistics are more complex both for organizers (due to seperate start and finish lines) and competitors. There is a limit on the length of cat 5 races, I beleive it's 60 or 75 miles. But some races can get a special approval to go longer.