The Rock 'n' Roll Arizona Marathon is a marathon held annually in Arizona on the Sunday before Martin Luther King, Jr. Day that links three cities of the Phoenix Metropolitan Area: Phoenix, Scottsdale, and Tempe. The marathon race can be used to obtain a qualifying time for the Boston Marathon. The race weekend also includes a half marathon, a 10K run, and a 5K run.

A half marathon is a road running event of 21.0975 kilometres —half the distance of a marathon. It is common for a half marathon event to be held concurrently with a marathon or a 5K race, using almost the same course with a late start, an early finish or shortcuts. If finisher medals are awarded, the medal or ribbon may differ from those for the full marathon. The half marathon is also known as a 21K, 21.1K, or 13.1 miles, although these values are rounded and not formally correct.