1. Map showing availability of hydrologic data published by the U.S. Environmental Data Service and by the U.S. Geological Survey and cooperating agencies, greater Denver area, Front Range Urban Corridor, Colorado [cartographic material] Yale Public content 1975. 2013-05-28T19:31:16Z. 2013-06-14T17:58:10Z. Hampton, E. R. Dept. of the Interior, U.S. Geological Survey. English. Public. Colorado, Denver Metropolitan Area, and Denver Metropolitan Area (Colo.).