Geography
Area: 181,040 sq. km. (69,900 sq. mi.); about the size of Missouri.
Cities: Capital--Phnom Penh (pop. 1.2 million), Battambang, Siem Reap, Kompong Cham, Kompong Speu, Kompong Thom.
Terrain: Central plain drained by the Tonle Sap (Great Lake) and Mekong and Bassac Rivers. Heavy forests away from the rivers and the lake, mountains in the southwest (Cardamom Mountains) and north (Dangrek Mountains) along the border with Thailand.
Climate: Tropical monsoon with rainy season June-Oct. and dry season Nov.-May.

Cambodia Geography
Cambodia is located on mainland Southeast Asia between Thailand to the west and north and Vietnam to the east. It shares a land border with Laos in the northeast. Cambodia has a sea coast on the Gulf of Thailand. The Dangrek Mountain range in the north and Cardamom Mountains in the southwest form natural boundaries. Principal physical features include the Tonle Sap lake and the Mekong and Bassac Rivers. Cambodia remains one of the most heavily forested countries in the region, although deforestation continues at an alarming rate.
source: http://www.state.gov