7 things to know before the Marine Corps Marathon On Sunday, more than 30,000 people will hit the streets of Washington D.C., and Arlington, Virginia, to participate in the Marine Corps Marathon and 10K. A howitzer will fire to signal the start of the race’s 42nd running. Find a full map of the marathon course here. Need more? Click here for our event preview, and visit the official race website here. You also can follow @Marine_Marathon on Twitter and track posts tagged #RunWithTheMarines for real-time race updates.