Sainyabuli, is the capital of Sainyabuli Province, Laos. It lies on Route 4 which along with Route 13 connects it to Luang Prabang, roughly 80 kilometres northeast by road and to the Thai border across the Luang Prabang Range in the southwest. A passport control point is in the area. Sainyabuli Airport lies southwest of the town. The capital stands on the banks of the Nam Hung, a tributary of the Mekong River towards the northern end of the province.