the mighty Mekong river forms a 465-mile (750-km) border between northeast thailand and laos. the valley along which it flows is a relatively fertile area in an otherwise arid region of thailand. it is possible to follow the length of the Mekong from Chiang Khan to Pha taem by road. some of the most attractive areas are west of nong Khai, where visitors pass through sleepy towns and villages of pretty wooden houses. south of the northern stretch of the Mekong lie the Phu rua, Phu Kradung, and Phu hin rong Kla national parks. Farther south is Ubon rachathani, by far the largest city in the region.
Nong Khai, Loei, Nakhon Phanom, and Ubon Ratchathani are the best bases from which to tour the area. Two train lines run through the region: a direct line, which divides at Khorat, connects Bangkok to Ubon Ratchathani and to Udon Thani. Travelers can pick up a connection from Udon Thani to Nong Khai. The best way to get around is by bus, rented car, or songthaew. Long-tail boats run on some sections of the Mekong River