Area code 231 serves northwestern Michigan, including Muskegon, Traverse City, and parts of the Upper Peninsula. Created in 1999 from a split with 616, this area is renowned for its natural beauty, lakeshore tourism, and outdoor recreation. The economy is driven by hospitality, agriculture, and small industry. Ten-digit dialing is required. Area code 231 is strongly tied to the state’s “Up North” identity and is a popular symbol for vacationers and residents alike.