Holden is a 140 km wide crater situated within the Margaritifer Sinus quadrangle region of the planet Mars, located with the southern highlands. Like Gusev, it is notable for an outlet channel, Uzboi Vallis, that runs into it, and for many features that seem to have been created by flowing water. It's believed that Holden Crater was formed by an impact between the Noachian to Hesperian Epochs. (wikipedia entry)