Chiang Khong is quite old. Some 1,200 years. It was a small kingdom for a long time, until the 19th century, when it became part of the expanding Bangkok/Siamese empire. At one point at the mainroad there is still a remain left from an old city wall.
Really nice is the place itself and it's surroundings. One can have a longer walk along the Mekong River banks, where it is quiet and some restaurants and guesthouses offer their services. Much boat activity is on the river, smaller longtail boats and really particular Laotion freighters build in a kind of houseboat style are to see around. They make their way between China and Luang Prabang in Laos. The river walk is a great opportunity for relaxation, especially after long bus trips.
Chiang Khong is a remote outpost at north Thailands border to Laos. It consists of one mainroad and a small net of sideroads. On the mainroad is too much traffic, but the sideroads are already quiet. There is a nice parallel way to the mainroad along the riverside. Here is almost no traffic at all, and many smaller restaurants and guesthouses are situated, offering a view over the Mekong River to Huayxai on the other river side in Laos.
There is some tourism here. Many backpackers travel through Chiang Khong on the way to Laos or back. Some stay longer, and it's worth to do so. Because, despite lacking big tourist attractions, the place is a nice, laid back one and has a beautiful surrounding. The people are generally very friendly and helpful. They consist mostly of trible people who settled down here together with Thai People and some Thai Chinese.
Don't miss the friday market! It's every Friday when many colorful dressed trible people from the mountains around, also coming over the border from Laos to Chiang Khong to sell their goods and to buy others.
The first choice to explore a new site is always on foot. One can stop everywhere spontaineous and look around, have a talk here and ask a question there. One can do a lot by simply walking. Particularly here, because Chiang Khong is no big place. To overcome distances there are small local busses, called 'songthaews'. Hitch hiking is an option. Hitch hiking was very common in Western countries in the 1960s and 1970s, but meaningless nowadays. Here it's still very easy.
There is some nightlife here. At the mainraod, south of the border-crossing are some smaller restaurants and pubs, where you can easily meet other travellers. Or have a look for "The Hub". Alan Bate, the operator, is a professional cyclist. His pub integrates a unique bicycle museum. Also some of the river bank Restaurants are quite nice to have a beer in the evening, as Khum Wang Restaurant or Baan Pung Rim Khong, where one can enjoy the view over the river apart from the mainroad.
When you walk along the Mekong River bank at one part you come along the Chiang Khong catfish museum. It claims that here were the first Giant Mekong Catfish bred (probably in the 1980s). It's a nice aquarium with some places to sit around. But, unfortunately, as tidy as the place looks, it's closed since many years. Because it's so nicely preserved there is hope it will be open once again. Maybe, when the new bridge over the Mekong is ready?
The Giant Mekong Catfish is considered the biggest freshwater fish and was once living in the whole Mekong River and the Tonle Sap River and Tonle Sap Lake in Cambodia. Nowadays it's an endagered species, as so many, many others...
More information about the Giant Mekong Catfish and the Chiang Khong Aquarium you find here.
Of course, as in any Thai place, there are plenty of temples. Wat Luang for example, situated between the mainroad and the Mekong River, is as old as Chiang Khong is, namely 1,200 years. The old stupas are remained from long forgotten times. It's particularly interesting to have a look at the temple paintings. They tell a lot of stories about Buddhas Life, but also about regional believes.
A martial temple painting in one of Chiang Khongs many small temples.