| Hers-Mort | |
| Pushpin Map: | France#France Occitanie |
| Mouth Coordinates: | 43.7744°N 1.3269°W |
| Subdivision Type1: | Country |
| Length: | 89km (55miles) |
| Discharge1 Avg: | 4m3/s |
The Hers-Mort (pronounced as /fr/; ; the "Dead Hers", as opposed to the faster-flowing Hers-Vif, or "Live Hers") is a 89.3km (55.5miles) long river in southern France, a right-bank tributary of the Garonne. Its average flow rate is 4m3/s. The Hers-Mort rises in the Lauragais region, near the village Fonters-du-Razès, in the Aude department. It flows northwest through the following departments and towns:
Payra-sur-l'Hers, Salles-sur-l'Hers
Villefranche-de-Lauragais, Baziège, Toulouse, Saint-Jory
It flows into the Garonne near Grenade-sur-Garonne. Its waters, augmented by the Girou which flows into its right bank, irrigate the market gardens around Toulouse. The Canal du Midi crosses the Hers-Mort near Villefranche-de-Lauragais via the Hers Aqueduct.