Cambria Sports Culture CIC Cymraeg

All walksCaerphilly and the Eastern Valleys

Caerphilly and the Eastern Valleys

Henllys Bog and Woodland

Marshy grassland and woodland on the edge of Cwmbran, protected for a butterfly that has disappeared from most of Britain.

Distance
3.1 mi / 5 km
Time
1 hr 45
Ascent
170 m
Difficulty
Moderate
Shape
Circular

Where it is

The circle shows the general area, not the exact start. Use the directions link below to get to the car park itself. Contours and paths shown are OpenTopoMap, drawn from OpenStreetMap data.

The route

Paths cross the reserve and loop through the woodland above. Wet underfoot in the grassland sections.

Worth knowing

  • Marsh fritillary butterflies fly here in late May and June.
  • The grassland is grazed to keep the sward suitable for their foodplant.
  • Wet ground; boots even in summer.

What you’ll see

Marshy grassland and its flowers, marsh fritillaries in early summer, and woodland.

Background

The site escaped drainage and improvement, which is why the habitat and its butterflies survive.