 Carbon County is the second largest natural gas producer in Utah (after Uintah County), with 94 billion cubic feet produced in 2008.The Green River flows south-southeastward along the county's east border.The lower central part of Carbon County is a continuation of Castle Valley in Emery County, but in Carbon the valley is ringed with mountains - the Wasatch Range to the west and northwest, and the Book Cliffs to the north and northeast.