The Perfect 10 (miles)
John Hanc calls the 10-miler "short enough to run hard, but long enough to brag about," in the February 2007 issue of Runner's World magazine.
You'll find runners hanging around after a ten-miler rather than leaving quickly, as they might after a 5k. Finishing is an accomplishment (even for a marathoner) and the travel time to and from the race is worth it.
For runners who experience a slower than expected first couple of miles, the ten-miler offers ample time to pick up the pace and compensate for a slow start.
Nine 10-milers attracted 2,000 or more runners in 2005, according to the Running USA Race Information Center. The largest were: Army Ten-Miler in Washington DC (13,271 finishers), Broad Street Run in Philadelphia PA (12,050 finishers), Cherry Blossom Run in Washington DC (8,657 finishers), and Crim Festival 10-miler in Flint MI (6,739 finishers).
Still, most 10-milers are small events. They're often positioned to coincide with training schedules of local marathons. Some are marathon-effort equivalents for runners who shun the 26.2 mile distance. Others are merely embellished training runs staged by local running clubs.
If you are considering producing a 10 mile race, remember you'll attract a smaller field than in a 5k, since fewer people are capable of running the longer distance. Registrants will be more frequent runners and racers, may have specific training goals, and will usually be willing to travel longer distances to get to the race.
Remember that a 10-miler is not a fun run. Runners are serious about the race - even if they are slow. Get your basics in place - course design, aid stations, fluid replacement, split times, traffic control, finish line management - before you add fun-filled amenities.