A half marathon is a roa running event of 21,097.5 meters, or 13 7/64 miles, about 13.1 miles. It is half the distance of a marathon and usually run on roads. It is a popular race for intermediate runners, long enough to be a serious challenge but not requiring the level of training of a marathon. In consequence, many towns and cities hold annual all-comers half marathon races through their streets. It is also common for a half marathon event to be held concurrently with a marathon, using almost the same course with an early finish.