One code for the whole state
Wyoming is one of the rare states that never split its phone territory.
307 has covered every corner of it since 1947, from Cheyenne in the southeast to Gillette in the Powder River Basin. That makes the prefix unusually strong: anyone in the state sees it as familiar. For a business trying to earn trust across long distances, that recognition is worth a lot. A 307 caller ID says you are part of the state, not just selling into it.