Car park on the lay-by at Le Marais between the D27 and the D132.
(S/E) Follow the D132 (Route des Bruyères) briefly and, at the bend, continue straight on along the Chemin des Sablons. Head down to the left along the wide stony path to the road (D27). Turn right onto it for a few metres.
(1) Leave the return route on your right, continue straight ahead, cross the Rémarde and carry on to the next junction. Turn left along the D132, follow the GR® signposting whilst staying on the left-hand side of the Route de Saint-Chéron. Walk about a hundred metres to the “Saint-Chéron 4” sign.
(2) Just before the sign, turn right onto the GR® which climbs between the hedges. Follow it uphill through the Bois du Marais, then turn left and follow it for about 400 m.
(3) Turn right onto a path (PR®) leading down towards the Orge valley to the south. On leaving the woods, leave the PR® and take the path on the left which stays along the edge of the woods and leads to the entrance to Saint-Chéron, then to a Stop sign before the D116.
(4) Cross it (take care) and head down Rue du Coteau Nord. Cross the railway line and continue towards Saint-Évroult. At the junction, cross carefully and continue straight on towards Le Mesnil.
(5) Cross the Orge and, at the T-junction, turn right along Rue de Blancheface for about 200 m to find the start of Chemin de la Garenne.
(6) Head left up the tarmac cul-de-sac between two buildings; this continues as the Chemin de la Garenne. Leave the woods and continue southwards to the path that bends to the right, near a row of trees at a place called La Boissière.
(7) Follow the GR®1 westwards (to the right) to the hamlet of Le Mesnil. Cross Le Mesnil following the yellow markings. Atthe first junction, turn right, then at the stop sign, turn left onto Rue Jourdin. Follow this road to Place du Ménil (bus stop).
(8) Turn right just after the bus shelter and continue on the GR®. At the end of the tarmac road, continue on the GR®. It curves sharply to the right and enters the woods, then turns left and right before descending into the wooded valley, reaching a junction of paths and tracks.
(9) Continue along thePR® to the right. On leaving the woods, cross the field to reach the junction of two roads. Cross thefirst road and follow the road opposite, which climbs gently, until you reach the bend to the left.
(10) Leave the road and follow the Sente de la Princerie, which starts next to a property, then descends and leads onto the Route de Blancheface in Sermaise. Turn left until you reach the junction opposite the town hall.
(11) Turn right onto Avenue Paul Blot until you reach the roundabout. Go round it on the right and continue straight ahead along the path that runs between two properties, further on passing under the railway line to join the wide path alongside the track. Follow it to the left then turn immediately right onto the path that climbs northwards and enters the woods. Continue until you come out of the woods.
(12) Head up the path opposite, still heading north, and cross the fields to reach the edge of the Marais woods. Turn left onto the PR® path along the edge of the woods until you reach the Ferme des Sueurs. After the pond, turn right onto the Route des Sueurs, which descends towards Val-Saint-Germain to the north. After about 400 m, the road crosses a wide path marked in blue (CR30) which veers off to the left.
(13) Follow it, keeping north. It crosses the road that winds downwards. Continue, passing the riding school, and emerge onto the Chemin des Morandières in Val Saint-Germain. Continue to the Rue du Village (D27).
(14) Cross at the traffic lights, turn left then immediately right onto Rue de Bouville. Follow it to the Stop sign, opposite which is Chemin des Bienfaits. Follow this path, leaving Voie des Sources behind, and go to the end of Chemin des Bienfaits, signposted on the right as a dead end. Reach the junction with Chemin de Houdoux, which turns left.
(15) Turn right to continue along Chemin des Bienfaits, which descends to the right. Continue along it until the junction with Route de Granville, under the high-voltage power line.
(16) Turn left and follow the road, which remains level before taking a first turn right then left and joining the D27 at the junction you passed on the way out.
(1) Turn left immediately, retrace your steps along the path running alongside the wall, which climbs slightly, then take the Chemin des Sablons on the right, running alongside the horse paddocks, to reach the car park on the central reservation (S/E).