If you get a new phone and number you will not be getting one with a 405 area code. According to the North American Numbering Plan Administrator the 405 area code will soon run out of numbers. The new area code will be 572 for Hennessey and surrounding counties that currently have 405. But wait there’s more! Starting next January you will also have to dial all 10 numbers even for a local call. Remember when you could dial only 4 digits to reach someone in the Hennessey area?