Area code 901
Area code 901 is an area code in the U.S. state of Tennessee. Originally it was the area code for the entire state, but now it is limited to the southwest corner of the state, including the city of Memphis.
Original assignment 
Under the original 1947 North American Numbering Plan, area code 901 covered the entire state of Tennessee.
Splits and overlays 
1954 split 
In an area-code split that was a flash-cut sometime during 1954, area code 901 was restricted to West Tennessee; while the eastern two-thirds of Tennessee—essentially, the entire state east of the Tennessee River—were reassigned the 615 area code.
2001 split 
Despite the presence of Memphis, the state's largest city, west Tennessee is not as densely populated as the state's other two Grand Divisions. As a result, 901 remained the sole area code for West Tennessee for 47 years.
However, by the turn of the century, 901 was close to exhaustion due to a proliferation of cell phones and pagers in the Memphis area. On September 17, 2001, area code 731 was assigned to most of the old 901 territory outside of the immediate Memphis area. Currently, area code 901 serves only Shelby and Tipton counties and portions of Fayette, Lauderdale and Hardeman counties—roughly coinciding with the inner ring of the Memphis metropolitan area.
See also 
|Tennessee area codes: 423, 615, 731, 865, 901, 931|
|West: 870||area code 901||East: 731|
|Mississippi area codes: 228, 601, 662, 769|
|Arkansas area codes: 479, 501, 870|