Nereus wrote:The northern border near Nan is wrong. The border follows the Mekong River.
Yes, the border with Laos is the quiz part, but no, it doesn't follow the Mekong and therein lies the problem. When the French colonial masters drew the maps/borders in 1907 they made it the way you see it and Thailand (Siam then) has been protesting it ever since. There still exists an active Thai/Lao panel that has been negotiating for 100 years +.
Quite a fierce mini-war was fought between the two in 1987-89 in what I call that arm pit area that juts into Thailand directly east of Uttaradit. I don't think Thailand has any hopes of getting all of the area back west of the river, but they seem adamant about that "arm pit" area. None of this is publicized much and I would bet most younger generation Thais don't even know about the issue.
As a side note, you'll notice that in the south the French did the same thing for that small chunk of land where Laos, Thailand and Cambodia meet. The Thai border is west of the river. I've never seen anything that Thailand is disputing that. Pete