The Houston Marathon is an annual marathon usually held every January in Houston, Texas, United States, since 1972. With thousands of runners and spectators, it is the largest single day sporting event in the city. It is run concurrently with a half marathon and a 5 km race. The 2007 race included the first-ever satellite running of the event, run simultaneously in Fallujah, Iraq. The races bring crowds of nearly one half million to view the runners.