Bigger than big. The MCM50K is the largest ultramarathon in the country and the only one held entirely in an urban setting. Participants share the start line with the Marine Corps Marathon in Arlington, VA directly adjacent to the Pentagon. The MCM50K begins prior to the MCM on October 30, 2022 and runs the entire MCM course with a 4.87-mile diversion at Mile 4.5 after runners cross the Key Bridge from Virginia into the nation’s capital. In addition to providing an official finish time, the MCM collects timing data for 50K runners at the 26.2 mile mark along the 50K course that can be used as a qualifying marathon finish time.

Deferment Re-Registration

Those who hold a current deferment will be receiving an email with instructions and a dedicated link on January 26. Registration will be open from January 26 to February 15. Current deferments must be used before any other means of registration. Otherwise, runner will risk forfeiting their deferred entry.

General Registration

MCM50K general registration will open on February 16.

Refundable Registration

Participants who are concerned they may not be able to participate in a Marine Corps Marathon Organization event can pay an additional service fee (12% of all items purchased, excluding event processing fees) for a 100% refund. The service fee will be the only amount not refunded. Refundable registration must be purchased as part of the registration process. Participants cannot go back and purchase once registration is complete.

For more information on the perils covered by refundable registration visit:

Please note, refundable registration does not cover the following:

  • If the participant does not attend the event because they are concerned about the coronavirus (COVID-19) or are self-isolating without a positive COVID-19 test or other non-COVID-19 communicable diseases leading to quarantines or travel restrictions.
  • If event organizers cancel the race.
  • Processing fees associated with items (entry fee, ancillary products, etc.) purchased during the application process.

The MCM50K shares the finish line with the MCM. Adjacent to the U.S. Marine Corps War Memorial, runners will pass under the famed MCM arch to receive a finisher medal from an awaiting Marine Corps lieutenant.

RRCA Championship

The Road Runners Club of America (RRCA) has awarded the Eastern Region Ultra Championship to the MCM50K for 2022. The 50-kilometer run will take place during the Marine Corps Marathon (MCM) Weekend on October 30, 2022 along with the MCM10K and the full marathon.

The RRCA Championship Event Series is the largest grassroots-organized running series in the U.S. with over 200 races participating that attract nearly 300,000 participants. The designation of the MCM50K as the RRCA District of Columbia Ultra Championship for 2021 means that runners competing in the event will be eligible for not only MCM age group and overall awards, but also RRCA honors.


2022 MCM Weekend Registration

Due to the number of expected deferment re-registrations from 2020 and 2021, the Marine Corps Marathon Organization (MCMO) will be rolling out the 47th Marine Corps Marathon (MCM) Weekend Events registration in stages.

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Run for a Cause with MCM Charity Partners

Choose an organization that resonates with you and click the links to connect directly with the organization and their representatives to find out how you can add purpose to your miles. Charities may have entries to the MCM, MCM10K and even the MCM50K.

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