Strike north from Phnom Penh along National Route 5, west of the Tonle Sap, and you’ll be following the route along which the Khmer Rouge retreated from Phnom Penh in 1979, ahead of the liberating Vietnamese forces. This is also the route that the invading Thai armies used in the opposite direction, as they repeatedly headed south to sack and pillage. Much of the northwest still shows clear Thai influence, especially in the style of the houses – not surprising given that the area came under Thai control at the end of the eighteenth century, and was only finally returned to Cambodia in 1946. These days the road is a busy transit corridor linking the capital to the Thai border and a trade route along which rice is transported from the sparsely populated but fertile plains to the more populous south. National Route 5 is in good condition, and the journey all the way to the border is about six hours. The train from Phnom Penh stopped some years ago, but the rails are being re-laid and freight trains are expected to run to Battambang in the not too distant future; it’s muted that the line will be eventually extended to Poipet on the Thai border.
The first two towns of any size along National Route 5 out of Phnom Penh are Kompong Chhnang and Pursat. A busy river fishing port, Kompong Chhnang takes its name from the terracotta pots (chhnang) which are produced here and used all over Cambodia, while quiet Pursat is home to marble workshops where you might see craftsmen at work. From both towns you can get out to visit the floating villages on the Tonle Sap.
North of Pursat is laidback Battambang, one of Cambodia’s largest towns with a lazy riverside ambience, colonial-era villas, shophouses and an Art Deco market. The surrounding province once had more temples than Siem Reap, although none was on the scale of Angkor Wat and most have long disappeared. The couple that remain are worth a visit, however, especially the hilltop site of Wat Banan, which you can see in a day-trip from Battambang.
On the Thai border in the far northwest, Poipet is increasingly used as a place to make a quick stop and change vehicles on the way between Bangkok and the temples at Siem Reap. If you’re travelling along this route it’s well worth breaking your journey at Sisophon, the crossroads town at the junction of national routes 5 and 6, to visit the rarely visited Banteay Chhmar, a ruined Angkorian temple which is still completely unrestored and overgrown by jungle.
It was to the mountainous border that the Khmer Rouge fled after their defeat, and from here that they waged a disruptive guerrilla war until 1996; in the far north, the remote Dangkrek Escarpment remained their foothold until the death of Pol Pot in 1998. The war was vicious and both the government and the Khmer Rouge laid land mines; the border is the most heavily mined area of the country and under no circumstances should you wander from defined tracks.