What is what area code is 307?

Area code 307 is the area code for the entire state of Wyoming in the United States. It was created in 1947 as one of the original area codes established by the North American Numbering Plan. The 307 area code covers cities such as Cheyenne, Casper, Laramie, Gillette, and Rock Springs. Wyoming is sparsely populated, so area code 307 has a relatively small number of telephone lines compared to other area codes in the United States.