Nong Khai is located in the valley of the Mae Nam Kong (Mekong river), which also forms the border with Laos. There are highlands to the south. The Laotian capital Vientiane is only 25 kilometers away from the provincial capital of Nong Khai. The Thai-Lao Friendship Bridge, which connects the two countries, was built jointly by the governments of Thailand, Laos and Australia, and was opened in 1994.