sentences:  The county lies totally within the Piedmont physiographic region.The topography of the county is generally gently rolling with several higher hills rising above the general terrain.One of these hills, Terrells Mountain, on the Orange County line is the transmitter site for several radio and TV stations for the Raleigh-Durham market, including WUNC-TV 4, WDCG (G105), WNCB (B93.9), and WUNC 91.5 FM (NC Public Radio).