Anyone over the age of 14 can run the MCM. Unlike the Boston Marathon, you don't have to qualify to enter. And in spite of the marathon's name, you don't need any sort of connection to the military to sign up, either.
Although you need strong legs to complete the 26.2-mile (42.2-kilometer) race, you need even quicker fingers just to register. The race is so popular that it often sells out quickly. The 2010 marathon filled in about six days -- with registration capped at 30,000. In fact, when registration opened on April 7, 2010, nearly 24,000 people signed up in the first 24 hours [source: Marine Corps Marathon].
That's not even the fastest sell-out time. The fastest ever registration happened in 2005, when the race filled in about 62 hours. In other words, if you want to be a part of the MCM, be ready to register as soon as possible.
If you missed the initial registration, you can still participate. You can register to run for the roughly 80 charities that are part of the MCM Charity Partner Program. Many people take advantage of this opportunity. Organizers expect about 2,000 runners to hit the course in support of a charity.
Those who don't register in time for the marathon, or who haven't trained for a distance this long, may want to run the MCM 10K race instead. The 10K runners start in the same location, but one mile (1.6 kilometers) into the route, they cross the Potomac River into Crystal City, where their route runs parallel to the marathon. Just like the marathon runners, the 10K runners finish at the Marine Corps War Memorial.
Like many marathons, the MCM's popularity carries beyond the area surrounding Washington, D.C. The 2010 race has entrants hailing from all 50 states. Runners from more than 40 countries make appearances, too.
Most runners simply run for themselves, but you can also enter a team and run the MCM as a group. If you enter as a team, you can have three to five teammates, however, only the top three finishers will have their times counted towards your team's overall performance.
Teams can be all male, all female, mixed, or runners from the Master's division (all 40 or older). Team members must all be a part of the same organization, such as the military, or a corporate team, club, government group or other entity.
In addition, there's a Challenge Cup competition at each MCM, in which the British Royal Navy and Marines send teams to take on the U.S Marine Corps team. The Challenge Cup has both a men's and women's division.
If you complete at least five MCMs, you can join the MCM Runners Club. Entry is free and guarantees your registration into the next year's marathon. This is an easy way to avoid missing out on a race that fills up fast.