Area code 612 is part of the North American Numbering Plan of the public switched telephone network for the city ofMinneapolis, Minnesota and a few surrounding areas such as Fort Snelling, St. Anthony and Richfield. By geographical area, it is the smallest area code in the state of Minnesota. However, like many other metropolitan area codes in the United States, the region used to be much larger, accounting for the entire Twin Cities region and a wide area surrounding it. At the outset, Minnesota received two area codes, 612 and 218. A 1947 map of the NANP showed the region defined as roughly the southeastern third of Minnesota. The rest of the state was 218, which formed an r-shaped region around the 612 area code. The separating line extended westward from Duluth to the center of the state, then down through the center. In 1954, the state was divided into three area codes. Part of the southern portion of the previous 612 territory, including Rochester and Mankato, was combined with the southwestern portion of 218 to form the new area code 507. The 612 area code was rotated out to cover most of central Minnesota, stretching from border to border from Wisconsin through the Twin Cities to South Dakota. In the process it absorbed some of 218's southern portion, including St. Cloud and Alexandria. The 218 region was reshaped to be more square, absorbing much of the old 612's northeastern portion, and now covered roughly the northern half of the state. This configuration remained in place for 42 years. In 1996, the northern and western portion of the old 612 territory, including almost all of its territory outside of the Twin Cities, became area code 320. This was intended as a long-term solution, but within a year 612 was back to the brink of exhaustion due to the Twin Cities' continued growth and the proliferation of cell phones and pagers. In 1998, the 612 region was roughly split in half, mostly following the Mississippi River. Minneapolis and the area west of the Mississippi retained the old code, while most of the area east of the Mississippi—including St. Paul—became the new area code 651. This was intended to be a long-term solution for exchanges in the Twin Cities. However, the Twin Cities are not only home to most of the state's landlines, but most of its pagers and cell phones as well. This brought 612 to the brink of exhaustion again within less than a year of the 651 split. As a result, the 612 code shrank to its current size in a three-way split that took effect in 2000. 612 was reduced to Minneapolis and a few suburbs to the north and south. The northwest suburbs became area code 763 while the southwest suburbs became area code 952. The eastern half of the University of Minnesota, Twin Cities campus, in the St. Paul suburb of Falcon Heights, is a notable exception to the regional numbering plan. Because of an integrated phone system linking both campuses, the Falcon Heights campus remained in 612 after the 1998 split. 612 is one of the few urbanized area codes without an overlay, making Minneapolis one of the few major cities where seven-digit dialing is still possible. Under current projections, it will stay that way until at least 2039. The area code splits in the Twin Cities are unusual because they split along municipal, rather than central office, boundaries. This led to a sizable number of exchanges being divided between two area codes, and a few being divided among three. The four Twin Cities area codes comprise one of the largest local calling areas in the United States; with a few exceptions, no long-distance charges are applied from one part of the Twin Cities to another. Portions of area codes 320 and 507 are local calls from the Twin Cities as well.
