Park in the church car park along the D73.
(S/E) Head towards the traffic lights (south-west) on Rue Carnot, on the left as you leave the car park, where you turn left. Go up Rue du Château until you reach a complex crossroads (halfway along, you will pass a very pretty old market hall). Turn right (signposted "Les Tournelles" and below "Maison de retraite").
At the first crossroads, go straight ahead. Then follow the signs that direct you down to the right until you reach the D73.
(1) At the D73, turn left, then left again 40 metres further on (Chemin de Prévarel).
Please note: although you will pass the Croix du Moine Mort, ignore the signs that tell you to turn left. You will do this when you reach the Château de Pupetière.
Continue along the hillside on a small paved road. When the pavement ends in front of a house, look straight ahead and take the grassy path (it blends in a little with the field on the right). Continue along this path until you reach the pretty hamlet of Mallein (Malin on the IGN map; water point).
(2) Continue straight ahead (sign for "Château de Pupetières"). You will suddenly come out into a clearing with the astonishing Château de Pupetière below. Destroyed during the Revolution, it was rebuilt
(3) Walk back and forth to the castle. Then retrace your steps and follow the track that climbs up to the right towards the "Croix du Moine Mort" (sign - yellow markings).
(4) Climb up the trail along the Combe Férouillat. Keep following the yellow markings for a while. When you come to another slightly wider trail (at a 45° angle), turn right and then take a path on the left.
(5) This path leads to the Croix du Moine Mort. When you reach the cross, take the first path on the left (signposted "Virieu 7.4km").
(6) Follow this path for a while, then exit halfway out of the woods. You will see fields on your left. Your path becomes paved.
(7) You will come to a crossroads and follow the Chemin de Longet to the right. A little further on, leave the yellow markings you have been following until now and go straight ahead instead of following them to the right.
(8). You will come to a group of houses. At the fork, turn left. Further on, you will see a sign in front of you indicating "no vehicles over 3.5 tonnes".
(9) Turn right, then very quickly left and follow the yellow markings. Enter the hamlet of Layat. At the corner of a house, take a dirt track on the left and pass the fountain. At the end of this track, the imposing Château de Virieu is opposite, below.
Head towards the castle. Shortly before reaching it, you will see signs on the right indicating the footpath that leads to the village of Virieu.
(10) Go to the castle and then turn back to take the footpath.
(11). It is very steep. The clay soil is covered with dead leaves, so be careful. You will arrive at the bottom of the valley. At the end of the path, you will come to a road. Take the lane on the left (no entry).
(12) To cross the village of Virieu, turn right at the first crossroads onto Ruelle de la Petite Charrière.
At the end of this lane, turn left onto Rue du Champ de Mars and you will come back onto the D73, which you take to the left until you reach the church car park (S/E).
To avoid the steep section after the château de Virieu, we went down to the left alongside the château and joined the small road.