The area code 513 serves southwest Ohio including Cincinnati and its many suburbs as well as the cities of Hamilton, Middletown, Lebanon, Trenton, and Oxford; it is one of the original area codes established in 1947. It formerly covered a larger area of Southwestern Ohio, which has since been split into area code 937. A new area code 283 has been assigned to overlay the current 513 area, but this has been delayed as the 513 area code has not yet been depleted of available numbers.

Although Cincinnati represents only a fractional geographical area in which area code 513 is used, it is generally accepted in pop culture that “The 513″ is a reference to Cincinnati and/or its surrounding neighborhoods.