Area code 513

North American area code 513 serves southwest Ohio including Cincinnati and many surrounding cities, such as Forest Park, Hamilton, Lebanon, West Chester, Mason, Maineville, Middletown, Norwood, Oxford, Harrison, Cleves, Miamitown and Trenton.

It is one of the original area codes established in 1947, and originally covered the entire southwest quadrant of the state. In 1996, however, most of the northern and eastern portion of the old 513 territory, including Dayton, was split into area code 937. The split came about mainly due to the proliferation of cell phones and pagers. The supply of numbers was further limited because the Cincinnati LATA extends some distance into Northern Kentucky and southeastern Indiana, and several numbers in northern Kentucky's 606 (now in 859) and southern Indiana's 812 were not available for use. Indeed, years after the introduction of number portability, 513 is still used to this day by a large number of cell phone users on the Kentucky and Indiana sides of the Cincinnati area.

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