The Thai–Laotian Border War (December 1987 – February 1988) was a short confrontation between Thai and Laotian forces. It was caused by a dispute involving the map made by French surveyors in 1907 to mark the borders between Siam and French Indochina in the southern Luang Prabang Range mountain area. Ownership of the village of Ban Romklao on the border of Phitsanulok Province and three small border villages on the edge of Uttaradit Province was left unclear. (This is the same map underlying the Cambodian–Thai border dispute. The agreed factor in determining ownership was the natural watershed, but the French map makers at times ignored this.)