Map 13 of Maps of SEA in the 1960s

East West Corridors

The other road out of Mu Gia, Route 23, led south for 15 miles before turning to the west.  While the turn to the west may have suited the original road builders, the routing was not the most direct to support a war in South Vietnam .  So, the North Vietnamese had already started a second road south from that point.  The new road, which the Americans labeled as Route 911 and 91, provided a shorter routing to Route 9.  The new road was also referred to as the eastern corridor while Route 23 was called the western corridor. 

Since the eastern corridor was more direct and less subject to flooding than the old road, Routes 911 and 91 carried the majority of the truck traffic.