The most populous cities in area code 307 are: Fe Warren Afb, Casper, Gillette, Cheyenne, and Jackson.
Other cities in the 307 area code include: Shirley Basin, Sheridan, Laramie, Rock Springs, Riverton, Cody, Evanston, Lander, Powell, Green River, Torrington, Buffalo, Rawlins, Pinedale, Wheatland, Douglas, Yellowstone National Park, Afton, Cokeville, Worland, Kemmerer, Thermopolis, Freedom, Sundance, Glenrock, Medicine Bow, Newcastle, Hanna, Encampment, Fort Bridger, Jeffrey City, Manville, Dubois, Big Piney, Lovell, Lyman, Alta, Shoshoni, Baggs, Alva, La Barge, Farson, Beulah, Moran, Van Tassell, Lagrange, Aladdin, Moorcroft, Greybull, Basin, Alpine, Pine Bluffs, Upton, Guernsey, Midwest, Meeteetse, Burns, Carpenter, Glendo, Chugwater, Burlington, Osage, Kaycee, Rock River, Ten Sleep, Deaver, Albin, Parkman, Clearmont, Crowheart, Hyattville, Arvada, Lance Creek, Lonetree, Garrett, Rozet, Wolf, Moose, Lingle, and Saratoga.
Casper is a city in and the county seat of Natrona County, Wyoming, United States. Casper is the second-largest city in Wyoming, according to the 2010 census, with a population of 55,316. Only Cheyenne, the state capital, is larger. Casper is nicknamed "The Oil City" and has a long history of oil boomtown and cowboy culture, dating back to the development of the nearby Salt Creek Oil Field. In 2010, Casper was named the highest-ranked family-friendly small city in the West, and ranked eighth overall in the nation in Forbes magazine's list of "the best small cities to raise a family". Casper is located in east-central Wyoming at the foot of Casper Mountain, the north end of the Laramie Mountain Range, along the North Platte River.
Gillette is a city in and the county seat of Campbell County, Wyoming, United States. The population was estimated at 31,797 as of 1 July 2013. Gillette is centrally located in an area involved with the development of vast quantities of American coal, oil, and coalbed methane gas. The city calls itself the "Energy Capital of the Nation," noting that the state of Wyoming provides nearly 35% of the nation's coal. Over the last decade Gillette saw a population increase of 48% from the 2000 census of 19,646 residents.
The 307 area code lies within the Mountain Daylight Time Zone (or MDT). The current time in Mountain Daylight Time is 2:14 AM on Apr 21, 2023.