Harmakhis Vallis is a valley near Hellas Planitia, Mars. It has been identified as an outflow channel, the site of catastrophic floods of water during Mars' past.

Gullies are also common on the wall of Harmakhis Vallis, as seen the image below. Some authors have suggested these structures indicate geologically recent flow of small quantities of water across the surface.

• Dao Vallis
• Reull Vallis

Further reading

• Bleamaster, L, Crown, D (2004). Morphologic Development of Harmakhis Vallis, Mars (PDF). Lunar and Planetary Science Conference.{{cite conference}}: CS1 maint: multiple names: authors list (link)
• Price, K (1992). Geologic Mapping of Part of Harmakhis Vallis Region, Mars: Evidence of Multiple Drainage Events. Lunar and Planetary Science Conference. Bibcode:1992LPI....23.1107P.

• HiRISE image of Harmakhis Vallis wall