Circular route from Saint-Hernin to the Kerlosquer viaduct along the banks of the Trieux

Just a stone’s throw from Guingamp, explore the south-western countryside of Ploumagoar, starting from Saint-Hernin. From wild valleys to country lanes, make your way to the right bank of the Trieux, where the river is still somewhat torrential, then visit the Kerlosquer Viaduct, which bears a passing resemblance to the ‘Bridge on the River Kwai’. Then enjoy the centre of Saint-Hernin with its beautifully restored heritage.
You’ll have no trouble at all on this route, which combines all sorts of paths and offers you, by turns, lovely shelter beneath the canopy of trees and completely unobstructed views of the surrounding countryside.

Details

91188183
Creation:
Last update:
Last review:
  • Walking
    Activity: Walking
  • ↔
    Distance: 10.21 km
  • ◔
    Average duration: 3h 20 
  • ▲
    Difficulty: Moderate

  • ⚐
    Back to start: Yes
  • ↗
    Ascent: + 154 m
  • ↘
    Descent: - 148 m

  • ▲
    Highest point: 130 m
  • ▼
    Lowest point: 75 m
  • ⚐ Country: France
  • ⚐ City: Ploumagoar (22970)
  • ⚑
    Start/End: N 48.534885° / W 3.14029°
  • ❏
    IGN map(s): Ref. 0816SB
  • Hour-by-hour weather

Description of the walk

The start is on Rue de l'Allée on the outskirts of Saint-Hernin, on a grassy square.

(S/E) Head towards the village centre and, opposite the wash house, turn left. Turn left again a few metres further on, into Rue Goasnou. Leave the village and, after crossing a stream at the edge of a large estate, look out for a signposted path leading down to your left.

(1) Follow this path which runs along the edge of the property, and head down into the forest, quickly heading north-west. At the first junction of paths, turn left towards the stream. Cross it and turn right. Follow the bank and soon turn left, climbing slightly and following the course of another stream. Follow this path until you reach a tarmac road, Rue de l’Allée (or de Bel Air).

(2) Turn right, ignore the first road leading towards the hamlet and, at the next junction, take the road on the right which enters the undergrowth. Continue downhill, ignoring the various trail junctions you come across. You will reach the end of the trail at the edge of the Route de Bourbriac, D8.

(3) Do not join the main road, but head for the side road on your left, Rue du Moulin à Fouler. Further on, at the first junction, at elevation 105, turn right and continue. Pass the junction with a dirt track at the 122 mark (great view of Guingamp), then the one at the 118 mark. Shortly afterwards, you’ll come to a left-hand bend and a junction before Kerlidiguez.

(4) Leave the main road by turning right onto this track which winds down between fields and woodland. After a right-hand bend, at the end of the pasture, the track becomes a narrow path leading down to the banks of the Trieux. Along the riverbank, head left and, as you leave the pine forest, turn left, following the edge of the meadow. Climb up to reach the village, and arrive at a double junction. Ignore the first one and the road leading off to the left. Arrive at the second junction.

(5) Take the Route de Kerlosquer on the right, pass the access road to the mill, and reach a bend at the entrance to the hamlet.

(6) Look out for the path leading off to the right through the vegetation, towards the Kerlosquer Viaduct. Walk there and back to this relic of the past.

(7) Return to the road, then turn right, leave the hamlet, and go straight on at the first junction. You will reach a crossroads at the 126m mark.

(8) Head left, continuing along the main road. You will then reach the village of Saint-Hernin, ignoring the side roads, and arrive at the wash house. Enjoy the site, then turn left onto Rue de l'Allée and return to your car park (S/E).

Waypoints

  1. S/E : km 0 - alt. 120 m - Car park on Rue de l'Allée
  2. 1 : km 0.76 - alt. 106 m - Junction with Rue des Ajoncs d'Or
  3. 2 : km 1.71 - alt. 118 m - Crossroads of the footpath and Rue de l'Allée
  4. 3 : km 2.68 - alt. 76 m - Junction near Route de Bourbriac
  5. 4 : km 4.76 - alt. 117 m - Junction before Kerlidiguez - Trieux (fleuve)
  6. 5 : km 6.67 - alt. 118 m - Crossroads in Kerlidiguez
  7. 6 : km 7.76 - alt. 103 m - Start of the trail at the bend in Kerlosquer
  8. 7 : km 8.05 - alt. 94 m - Viaduc de Kerlosquer
  9. 8 : km 9.08 - alt. 127 m - Crossroads at elevation 126
  10. S/E : km 10.21 - alt. 120 m - Car park on Rue de l'Allée

Worth a visit

Reviews and comments

4 / 5
Based on 1 review

Reliability of the description
4 / 5
Ease of following the route
4 / 5
Route interest
4 / 5
cnu25
cnu25

Hello @mary2309....I walked and mapped this route in February after the winter rains, so there was more tarmac than usual, but I hope you enjoyed it....Have a nice day

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Mary2309
Mary2309

Overall rating : 4 / 5

Date of your route : Mar 23, 2026
Reliability of the description : ★★★★☆ Good
Ease of following the route : ★★★★☆ Good
Route interest : ★★★★☆ Good
Very busy route : No

A bit too much motorway, not enough country lanes.

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