Gar Williams Half Marathon

Sunday, December 3, 2023 • Carderock, MD • Course Map

Run in previous years near the Belle Haven Marina area, since 2010 the Gar Williams Half Marathon has been run along the Potomac River and the C&O Canal Path, along an out-and-back course that starts and finishes at the Carderock Recreation Area, which is part of the National Park Service along the George Washington Parkway.

Named for the past president of both the Road Runners Club of America and the DC Road Runners club, this race is described by participants as a hilly, challenging course — and is always run in some of the Washington area’s coldest weather.

All those interested in participating in this low-key event are asked to make the drive to Carderock Recreation Area (not the Carderock Recreation Park) in Carderock, Md., which lies just south of the famed Congressional Country Club.

The race usually draws between 150 to 200 runners out for what can be a very cold race — or can be sunny and mild, depending on the weather in the days leading up to the race.

Race Weather & Climate

Located in central southern Maryland, about 11 miles northwest of downtown Washington, D.C., Carderock typically sees December temperatures that average between 46°F and 29°F, while precipitation amounts average just over 3.2 inches for the month.

On the day of the race (Dec. 3), the average high is 48°F and the average low is 33°F.

Past Results

Course Map

See the race route map for the Gar Williams Half Marathon here.

Starting Time

9:00 AM


  • $10 for non-DC Road Runners members
  • Free for members


To reserve your spot in the 2023 running of Carderock’s Gar Williams Half Marathon, register online at the event website here.

Official Race Website


Ever run in the Gar Williams Half Marathon? Share your impressions here, or post your review in the Comments below.

See more races in: December, Maryland