Koh Ker is about 80 miles NE from Siem Reap and it was briefly the capital of the Khmer Empire. It is not a single temple but former city with a group of temples scattered over a wide area (qv Grand Circuit, Siem Reap). It can take most of a day to look at all the accessible temples. Trying to combine Koh Ker with Preah Vihear is like trying to combine Musee d'Orsay with the Louvre in a day. Even combining it with Beng Melea is not recommended unless you are thinking about a visit to 2-3 temples only.

Prasat Thom is the best known temple with Prang, the magnificent stepped pyramid. The main car park is near and there is a ring road around Rahal, the huge baray. Going clockwise, there is a group of temples with the largest lingams remaining. Take care as the names of the temple known to the locals, sign posted on the road and on maps are not consistent.

Prasat Banteay Pichean Prasat Chrap, and Prasat Damrei are definitely worth a closer look. All are in bad condition but there are still some interesting carvings. Also these temples being brick, have a different atmosphere to stone ruins.

Prasat Pram, the last temple before leaving Koh Ker, is also worth a stop. As the name suggests, it is a goup of 5 towers with 2 towers covered in roots.

There are some facilities at the main car park, but nothing elsewhere. You should make sure that you have enough water, etc before starting for the satellite temples.

A day trekking tour is a delight in Koh Ker. The long leisure walk for about an hour through a brush of greens and gigantic trees is such a cool and wonderful sight to be upclose with nature. This is a remote archeological tour that will lead you to the ruins of the hidden temples in Beng Melea. The stones and rocks of the ruined temples remained untouched and unreplaced all through these years. I am amazed by how the government and the locals have preserved history through its original form. There is more way to go because at the far end of the trek and tour will make you mArvel at a more wonderful site.

This is an amazing wide area to explore, where the hords of tourists are still far away from coming.
I was here in the early morning with my driver Sokra on a three days Easy Rider tour by scooter, and we enjoyed each temple with no tourist around, being the only visitors for several hours. Prasat Pram is simply stunning with all those invasive creeping roots wrapping each prasat.
And when the sun rises the light is simply wonderful and you can be rewarded by magic photos.
Another must-see spot is the maya-like pyramid, Prasat Thom, that can be climbed easily, with a newly built safe staircase, allowing people to experience amazing views from the top.
The area is wide enough to need a quick way to move from one temple to the other on dirt paths, and a scooter proved to be the best choice, fast and safe.