Coming September 7, 2014. Touted as America’s Premier Triathlon, The Nation’s Triathlon is certainly a postcard-perfect race, and it benefits The Leukemia & Lymphoma Society. The 40K bike and 10K run routes are mostly flat, very fast, and closed to all car traffic. See many of Washington, DC’s historical landmarks along the way – Jefferson Memorial, Washington Monument, Lincoln Memorial, and Arlington National Cemetery to name a few. The 1.5K swim in the Potomac River is a very well-marked, loop route in 70 degree water. Noted in the Guinness Book of World Records as America’s most popular triathlon event, you won’t want to miss this one!