Start from Marest, small square on D89, at the junction with Rue de l'Église.
(S/E) Take the D89 towards Bours, cross the Clarence river and pass the school.
(1) Turn right onto Rue de Pernes, which climbs to the D916. Follow it to the right (with care) for about 200m, then turn left towards Pressy.
(2) At the top of the hill, take the path on the left. Pass under the HV power line and, just before the reservoir, take the left-hand path down to the hamlet of Noyelles.
(3) At the T-junction, turn right, then left to go back up to the D916. Follow it for a few metres on the left.
(4) At the fork, turn right into Rue du 8 Mai. Reach the D89, follow it to the right, cross the stream, and reach a crossroads.
(5) Leave the tarmac at this point and take the grassy road opposite, leading to Bours. At the tarmac, turn left, passing the church and reaching the beautiful Bours town hall (keep of the former château).
(6) Then turn right (beautiful square), and reach the D89.
Follow it a few metres to the left and take a small road on the left (opposite Rue de Valhuon) which joins Rue de Chametz near the stadium.
(7) Follow this to the right to join the D89. Turn left and, before the railroad tracks, turn left into Rue Blanche (mud at the farm).
(8) At the end (chapel), turn right on the GR®127, pass under the railroad line and, still on the GR®, turn immediately left. A good climb (now well laid out, with a bench offering a superb view) leads to the high point (elevation 172).
(9) Leave the GR® and continue straight ahead. Pass a farm, then turn left towards Bois Lanoy. Follow this good path (unfortunately often very wet) between the barbed wire. Gradually descend to arrive opposite the railroad (oratory).
(10) Cross it and follow Rue de l'Église back to the starting point.