 These spurs created narrow river valleys with steep ridges that frequently provided hideouts for PAVN/VC units or housed PAVN/VC command, control and logistical centers.The plain itself was bisected by the east-west Lai Giang River, which was in turn fed by two others, the An Lao, flowing from the northwest and the Kim Son, flowing from the southwest.These two rivers formed isolated but fertile valleys west of the coastal plain.