North-western Cambodia is a region of Cambodia and includes the provinces of Banteay Meanchey, Oddar Meanchey, Preah Vihear, Siem Reap and the part of Stoeng Treng to the west of the Mekong.
Much of the southern part of this region is very flat and fertile. The north is dominated by the Dangrek Mountains which form the natural barrier btween Cambodia and Thailand.
The region is served by Siem Reap - Angkor International Airport  (IATA: REP | ICAO: VDSR) which has has frequent domestic flights from Phnom Penh and is internationally linked from the following destinations:
The region is linked by road to Thailand. This road was completely re-surfaced in 2009 and runs from Siem Reap to Sisophon in the far north est of the region where it then crosses into Thailand at Poipet. This road journey takes about three hours.
The road from Phnom Penh to Siem Reap is much travelled and a bus journey will take 5 to 7 hours.
The magnificent ruins of several ancient Khmer cities at Angkor Archaeological Park cover some 400 sq km and this is one of the world's great monuments. These include the famous Temple of Angkor Wat and, at Angkor Thom, the Bayon Temple with its countless sculptural decorations. Angkor was declared a UNESCO World Heritage site in 1992 and UNESCO has set up a wide-ranging programme to safeguard this symbolic site and its surroundings.
Angkor itself has no accommodation and few facilities and the nearby town of Siem Reap is the tourist hub for the area.
If Angkor does not fill your appetite for ancient ruins, then there are more at Koh Ker to the north.
Tonle Sap is the largest freshwater lake in south-east Asia and a site of major conservation importance.