How many miles is a walkathon?

Excuse me, could you please clarify what you mean by "walkathon"? Is it a specific event or a general term for a walking competition? If it's a specific event, the distance can vary greatly depending on the organizer's intentions and the participants' abilities. However, if we're talking about a general walking competition, the distance can range anywhere from a few miles to a marathon-length distance of 26.2 miles. Could you provide more context or specify the event you're referring to so I can give you a more accurate answer?