proper) 1,339.7/km² Latitude 32°47' N Longitude 96°47' W Time zone Summer (DST) CST (UTC-6) CDT (UTC-5) Official website: http://www.dallascityhall.com/ Dallas is the third-largest city within the State of Texas , ninth in the United States , and together with Fort Worth and the Mid-Cities form the largest metropolitan economic area in the south-central