Thailand, officially the Kingdom of Thailand and historically known as Siam, is a country in Southeast Asia on the Indochinese Peninsula. With a population of almost 70 million, it spans 513,120 square kilometres (198,120 sq mi). Thailand is bordered to the northwest by Myanmar, to the northeast and east by Laos, to the southeast by Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the southwest by the Andaman Sea; it also shares maritime borders with Vietnam to the southeast and Indonesia and India to the southwest. Bangkok is the state capital and largest city.

Laos, officially the Lao People's Democratic Republic, is the only landlocked country in Southeast Asia. At the heart of the Indochinese Peninsula, Laos is bordered by Myanmar and China to the northwest, Vietnam to the east, Cambodia to the southeast, and Thailand to the west and southwest. Its capital and largest city is Vientiane.