The southernmost region of the Republic of Vietnam (South Vietnam) encompassed the vast Mekong River Delta, and area covering 10,190 square miles. Three major rivers run through the Delta, the Song Hou Giang (aka Bassac) and the Song Mekong, which broke into three large rivers (Song My Tho, Ham Luong, and Go Chien). The Nhon Trach delineated the Delta's eastern edge. In all there were some 1,500 miles of natural navigable waterways and 2,500 miles of man-made canals and channels. The canal system was begun in 800 AD and its expansion continued up to World War II. The nation's capital, Saigon, lies on the Delta's northern edge. Few roads and highways served the region with sampans and other small watercraft via the canals being the main means of transportation.