Which countries does the Mekong River flow through?
By Farflung ·
Past-prompt spoilers: this article reveals every accepted answer to this prompt.
Pin a country the Mekong flows through
The six answers are China, Myanmar, Laos, Thailand, Cambodia and Vietnam. The Mekong River Commission’s overview names the same six countries along the river’s course.
On this card a country counts if it has a bank on the Mekong; the river need not cross its land. That is how Myanmar and Thailand count: for both, the river is part of the border with Laos.
The answers and why they count
| Country and rarity | Why it counts |
|---|---|
| Vietnam Common | The river reaches the sea through the Mekong Delta in southern Vietnam. |
| Cambodia Uncommon | The Mekong runs through Cambodia, with the delta beginning around Phnom Penh. |
| Laos Uncommon | The Mekong runs through Laos and along parts of its border. |
| Thailand Rare | The river forms stretches of Thailand’s border with Laos. |
| China Elusive | The river starts on the Tibetan Plateau. In China, it is known as the Lancang. |
| Myanmar Farflung · Gem | Myanmar has a bank on the river along its border with Laos. |
The Commission’s geography guide traces the route and delta, while its regional guide explains the Lancang name. Printed page 7 of its Social Atlas of the Lower Mekong Basin describes the Myanmar–Laos and Thailand–Laos river borders.
Why Myanmar is the gem
Myanmar is this card’s gem, with the top rarity, Farflung. Follow the river south from China and Laos and Thailand come to mind; the country on the opposite bank is easy to miss.
The Commission’s Social Atlas shows that stretch: after leaving China, the Mekong is the border between Myanmar and Laos before it reaches Thailand.
The river the Mekong turns round
In Cambodia, the Tonle Sap River drains Tonle Sap Lake into the Mekong through the dry season. When the Mekong rises in the rains, it pushes water back up that river into the lake, and the Tonle Sap runs backwards. UNESCO explains the cycle.
The lake covers about 2,500 to 3,000 square kilometres at the end of the dry season and as much as 16,000 in the rains, five or six times as much (Wikipedia).
This list and its rarities reflect the answer key for the 13 October expedition, checked on 21 October 2026. Past answer lists can receive corrections.