Almost as mysterious as Xieng Khuang's more famous jars, this unique, unfenced collection of standing stones is thought to be at least 1500 years old. Spindly stones up to 3m tall are interspersed with disks that formerly covered funerary sites. With some over a metre in diameter, these 'families' of stones do have a certain magic. Chartered tuk-tuks from Sam Neua will ask around 500,000K return.
Access is up a rough, rutted track that cuts south from Rte 6 at Ban Phao (Km 35.3), 57km from Sam Neua. This track can be impracticably muddy for vehicles after any rain. The main site is right beside the track after 6km, around 800m beyond the obvious radio-mast summit. Some 2km back towards the main road, an orange sign points to the Keohintang Trail, which allows more intrepid visitors to seek out lesser-known megalith groups hidden along a partially marked two-hour hiking trail. Take the narrow rising path, not the bigger track that descends towards Ban Nakham. If you don't get lost, the trail should emerge back onto Rte 6 at Ban Tao Hin (Km 31.5), a tiny village without any facilities.
When driving between Sam Neua and either Phonsavan or Nong Khiaw, allow two hours extra for the very slow detour to the main site. Using public transport it is necessary to walk to and from Rte 6. Practicalities work out best if visiting between Sam Neua and Phonsavan: starting with the Vieng Thong–bound minibus, you'll have around six hours for the walk before the last Phonsavan/Vientiane-bound bus rumbles past.