Cambodia, officially the Kingdom of Cambodia, is a country in Southeast Asia on the Indochinese Peninsula, spanning an area of 181,035 square kilometres, bordered by Thailand to the northwest, Laos to the north, Vietnam to the east, and the Gulf of Thailand to the southwest. The capital and most populous city is Phnom Penh.

Mainland Southeast Asia is the continental portion of Southeast Asia. It lies east of the Indian subcontinent and south of Mainland China and is bordered by the Indian Ocean to the west and the Pacific Ocean to the east. It includes the countries of Cambodia, Laos, Myanmar, Thailand, Vietnam, and Peninsular Malaysia.