Following the Orge from Sainte-Geneviève-des-Bois to Athis-Mons

Departure from Sainte-Geneviève-des-Bois station (RER line C, on the sections between Paris and Saint-Martin-d'Étampes and between Paris and Dourdan-la-Forêt). Take the Place Franklin Roosevelt exit, on the side of platform 1 (Paris-Étampes or -Dourdan direction; if arriving in the other direction, take the underground passage).

No signage

(S) When you leave the station, turn left, pass a bicycle park on your left and cross Square Maurice Andin with a car park on your right. On a wide gravel path reserved for pedestrians and cyclists, stay parallel to a street on your right. Shortly before a slight descent and at a fork in the road, leave the path, cross the street at the pedestrian crossing and turn left up Rue Antoine Rocca (the right fork).

(1) At No. 15, turn left onto Chemin du Perray and walk along a wood on your left. Go through a forest gate and, at the next crossroads, turn sharply left towards the shooting range. A few metres after another forest barrier (incorrectly positioned on the 1:25,000 IGN map), turn right onto a path that enters the woods. Stay on the main path, which zigzags at the beginning, and ignore a path on the left leading to a picnic table.

(2) At a crossroads (green post on the right), continue straight ahead. Pass between three crenellated posts and you will come to a sort of clearing. Continue straight ahead, heading north, and leave a pile of stones on your left. At the end of the path (forest barrier), cross a road, turn left and take the bridge over the railway line. At the stop sign, go straight downhill towards the Orge Valley. At the next junction, continue straight ahead on a path between two fences. At the bottom, cross a secondary branch of the Orge and turn right. Walk along a pond on your left and take a footbridge over its spillway. At the information sign, turn right and cross the Orge on a footbridge.

From this point until the end of the hike, you will be almost entirely on the Promenade de l'Orge, marked by large signposts and information panels.

(3) Turn right and walk along a street (football stadium on your left). When the street turns right and before a bridge over the Orge, leave the street on the left, pass through a forest gate and follow a stabilised path with the river on your right. Ignore the first metal footbridge and cross the Orge on the second footbridge, which is made of wood. At the end of the footbridge, turn immediately left and follow the river on your left. At a crossroads (footbridge on the left), continue straight ahead and pass under the railway viaduct. Cross the Orge, ignore a footbridge on the left and walk between the main branch of the Orge on your right and a secondary branch on your left.

Red and yellow markings

(4) Cross the road and, about a hundred metres after the forest barrier, cross the Orge again. At the fork at the end of the footbridge, turn left and follow the river on your left. Pass under the road bridge and, immediately after, cross the Orge. Follow the river on your right and, shortly after a pond on your left, cross the Orge again. At the end of the footbridge, take the path furthest to the right. At a T-junction, turn right and take another footbridge. Then turn left to follow the lake, keeping a meadow on your right (view of a castle on the right). At a three-way junction (not shown on the map), turn left, staying as close as possible to the lake.

No markings

(5) At the T-junction, turn left (leaving the^GRP® trail to the right). At the crossroads (map), turn right towards the Duparchy nature reserve and walk along the Orge river on your left. Pass under the A6 motorway and, immediately afterwards, ignore a footbridge on the left. Cross a park with a pond on your right. At a fork, turn left. At the foot of a building, turn left and follow a small cement path. Walk along the Orge river (wire fence) with buildings on your right. At the corner of the last building, turn left onto a gravel path and go through a gate. Go through a second gate and continue along a narrow lane.

Red and yellow markings

(6) At the end, turn left onto Rue de Savigny. After a few metres and before the bridge, cross the street at the pedestrian crossing and turn right onto Promenade des Bords de l'Orge. At a roundabout (footbridge on the left), there are two paths ahead: take the left one and stay by the river. At the three-way junction that follows, turn left, cross a secondary branch and follow a wide, shaded path along the Orge (on your left). Cross the secondary branch again, ignore a path coming from the right and continue along the Orge.

(7) At the boundary between Viry-Chatillon and Savigny-sur-Orge, cross the road and first turn right then left to follow the direction of Les Belles Fontaines. Pass a football stadium on your right, cross the Orge, turn immediately right and walk along the allotments on your right on a small paved path. At the end, turn left.

(8) Turn right into the street (Allée des Serres). At the start of the bridge over the Orge, leave the street on the left and go down the spiral staircase leading to the concrete bank. Walk along the river on your right. Ignore a footbridge on the right and take the tunnel under the railway line. Then take the footbridge on the right that crosses the Orge, turn left and walk along the river on your left. Ignore a footbridge on the left and pass under the Pont des Belles Fontaines (note the double arch system).

(9) Then turn left and follow the Orge on your left. After a footbridge with blue railings (beautiful plane tree on the opposite bank), the river goes underground. Continue straight ahead into Allée de Thale. At the corner of Espace Marianne (town hall annex), turn left onto Grande Rue. Between numbers 37 and 39, turn left under a porch into Espace Culturel Jean Durix. After a staircase, turn right, pass under another porch and you will come out onto a street. Cross at the pedestrian crossing and turn left.

(10) After the bus stop, climb the stairs on the right leading to the Parc de la Mairie. At the top, follow the tarmac path on the left and leave the IUT on your right. At the crossroads at the foot of the imposing town hall, turn right. After about 100 metres, take a tarmac path on the left with a ramp on the right-hand side. At the T-junction, turn left and pass a pond on your right. At the corner of the town hall, turn right. At the next crossroads, continue straight ahead with a large lawn on your left.

(11) Ignore the access to a "city stadium" on your right and, immediately after, turn right and go through a small forest gate (the markings disappear here). At the next T-junction, turn right and walk past some monumental sculptures. Ignore a path on the left, go downhill and take a footbridge over a street. At the fork immediately ahead, take the right-hand cement path downhill. At the next fork, take the left-hand path, which climbs gently towards the Parc des Grottes.

(12) Cross a road at a hairpin bend and enter Parc des Grottes. Continue straight ahead on a wide gravel path. Pass a pond on the left and a viewpoint on the right. Shortly afterwards, go down the first staircase on the right. At the bottom, follow the street to the right. Take the first left, a descending staircase lined with plane trees.

Red and white markings

At the crossroads, follow Avenue de la Terrasse to the left (let the^GRP® continue straight ahead downhill). Ignore Avenue Gounod immediately on the left, walk alongside Lycée Marcel Pagnol and go around the Georges Carpentier Gymnasium on the left. Ignore a path leading off to the left into a wood and cross the river once again.

(13) Then turn immediately left and follow Promenade de l'Orge. At a fork, take the left path and stay as close as possible to the river. After a forest barrier, continue along the tarmac road. At the T-junction, turn left and take the bridge over the Orge. At the roundabout, turn right. Go straight ahead, ignoring all the side roads, and walk alongside the Collège Mozart.

(14) At the crossroads, cross the road and then first turn left then right to take Rue du Parc d'Athis (dead end). Continue straight ahead through a residential area. At the end, turn right towards Athis-Mons station (the purple line on the IGN map is not updated here). At the fork, turn left and walk along the Orge on your right (beautiful plane trees). Take the bridge on the right over the Orge, then turn left and walk along the river on your left on its cemented bank.

No markings

After a footbridge on the left, leave the^GR® trail on the right and continue along the concrete bank. Pass under the road bridge and then under the railway bridge. Cross the Orge river one last time on a footbridge and arrive at a road quay on the banks of the Seine, at the confluence with the Orge. Turn left and then take the first left. You will soon reach Athis-Mons station with access to the platforms, either immediately for a return journey to Étampes or Dourdan (track 1bis), or after taking the underground passage for a return journey to Paris (track 2bis) (E).

Train timetables: check the Transilien website.

For motorists: Sainte-Geneviève-des-Bois and Athis-Mons stations have car parks, so you can leave your car at one of them or at both.

Low-cut hiking boots or good trainers are suitable for this hike, which mainly follows stabilised paths and tarmac roads.

Dogs must be kept on a lead along the entire length of the Promenade de l'Orge, between (3) and (14). The space is shared with other users, who may be numerous at weekends: other walkers, runners and cyclists. A minimum of attention and courtesy is required.
N.B. The hike crosses the cemented bank of the Orge twice, just above the normal water level. In the event of flooding, these passages are likely to be impassable.

A detailed map is required (at least the one accompanying this description).

Resources along the way:
- Near Sainte-Geneviève-des-Bois station (S): bar-restaurant, bakery, pharmacy.
- In Juvisy town centre, between (9) and (10): bars, restaurants, shops, market.

Alternatives:
The route passes close to other stations on the RER C line, which offer alternative starting or finishing points:
- Épinay-sur-Orge station: direct access from (4).
- Savigny-sur-Orge station: access from (6) via the town market.
- Juvisy station: access from the town centre, between (9) and (10).

Hike completed by the author on 19 October 2017.

- Pleasant walks along the Orge. The Promenade de l'Orge is managed and maintained by the Syndicat mixte Orge Aval.
- Lac du Séminaire (5).
- Pont des Belles Fontaines bridge with its double archway system (9). Dating from 1728, it has been classified as a historic monument since 1914.
- Juvisy Town Hall Park, between (10) and (12). The monumental sculptures located after (11) come from the Pont des Belles Fontaines: they were transported there when the N7 road that supports the bridge was widened in the 1970s.
- Parc des Grottes after (12). More than just an artificial cave at the edge of a pond, this place is worth visiting for the extensive view it offers towards the east.