Enipeus Vallis is a valley in the northern hemisphere of the planet Mars. It is centered at lat. 37°N, long. 267°E in the Arcadia quadrangle (MC-3) between the large volcano Alba Mons and the Tempe Terra plateau. The valley follows a gently sinuous, north-south path for a distance of about 357 km (222 mi).USGS Gazetteer of Planetary Nomenclature. http://planetarynames.wr.usgs.gov/Feature/1803. It is likely an ancient watercourse that formed during the early Hesperian (or late Noachian) period,Moore, H.J. (2001). Geologic Map of the Tempe-Mareotis Region of Mars. USGS Geologic Investigations Series I-2727. http://geopubs.wr.usgs.gov/i-map/i2727/. around 3.7 billion years ago.Hartmann, W.K. (2005). Martian Cratering 8: Isochron Refinement and the Chronology of Mars. Icarus, 174, p. 317, Tbl. 3. .
