Phia Oac Phia Den National Park

Phia Oac rises to about 1,930 metres in western Cao Bang and is one of the few places in Vietnam where frost and occasional snow occur - most winters bring at least a hard frost, and the phenomenon draws Vietnamese visitors specifically. The forest on the upper slopes is mossy montane forest with rhododendron, unusual this far north-east. The French built a hill station here in the colonial period for the tin and tungsten mining in the district, and the villas are still there in the trees, roofless and overgrown, which is the mountain's other subject. It was made a national park in 2018.

What's there

• Frost most winters - and occasional snow, rare in Vietnam.
• Mossy montane forest - with rhododendron on the upper slopes.
• Ruined French villas - from the mining hill station.
• A national park since 2018 - upgraded from reserve status.

When to go

October to April; December and January for the frost. A full day.

Before you go

The road up is steep, narrow and dangerous in ice - which is exactly when people drive it. Fog sits on the mountain much of the year. Facilities are minimal. The villas are unstable ruins.

Nearby

Nguyen Binh is below; Cao Bang and the geopark loops are east.

Key facts