Data provided by USA Triathlon
Ironman Florida - 2,421 Finishers in 2012Panama City Beach, Florida - November 2, 2013 1 of 11
Moderate temperatures and a flat course make this one of the most popular Ironman events out there. The downside is that it's one of the more difficult races to get into.
Philadelphia Triathlon - 2,457 FinishersPhiladelphia, Pennsylvania - June 23, 2013 2 of 11
Enjoy racing through some of the most picturesque and historic setions of Philly. Highlights include a swim that goes downstream and a bike course that includes a section of the TD Bank US pro cycling championship race course.
Ironman 70.3 Augusta - 2,672 FinishersAugusta, Gerogia - September 29, 2013 3 of 11
This Peach State triathlon starts with a 1.2-mile swim in the Savannah River then takes entrants on a one-loop, scenic hilly bike course through Georgia and into South Carolina.
Malibu Triathlon - 2,717 Finishers in 2012Malibu, California - September 7, 2013 4 of 11
This event helps elevate triathlon's exposure drawing celebrities like Matthew McConaughey, Ryan Sutter and Mario Lopez. There are actually enough A-listers to warrant a celebrity racing category. The Southern California setting nealry guarantees good weather and great scenery. What more could you ask for in a race?
St. Anthony's Triathlon - 3,023 FinishersSt. Petersburg, Florida - April 28, 2013 5 of 11
Head to this Gulf Coast triathlon and grab a few rays with 3,000 of your closest friends.
USA Triathlon Age Group Nationals - 3,042 Finishers in 2012Milwaukee, Wisconsin - August 10-11, 2013 6 of 11
Photo: Lee Krohn/USAT
Participants in the Olympic-distance event must qualify by finishing in the top 33 percent (or among the top five finishers) at a regional championship or special qualifier, or among the top 10 percent at any USAT-sanctioned event. Registration for the sprint race is open. Find out if you have what it takes to race with the best age groupers in the country.
Nation's Triathlon - 3,166 Finishers in 2012Washington, D.C., September 9, 2013 7 of 11
Challenge yourself in the nation's capital at this triathlon that features a 1.5K swim in the Potomac River, a 40K bike course through D.C. and a 10K run through historical landmarks.
New York City Triathlon - 3,502 FinishersNew York City, New York - July 14, 2013 8 of 11
Join over 3,000 athletes who sign up to brave the waters of the mighty Hudson River before biking along Manhattan's West Side highway and finishing with a run through New York's famed Central Park.
Wildflower Triathlons - 4,761 FinishersBradley, California - May 5, 2013 9 of 11
Looking to put your skills to the test? With one of the most challenging courses anywhere, the Wildflower event is one of the premier triathlons in the world.
Chicago Triathlon - 5,303 Finishers in 2012Chicago, Illinois - August 25, 2013 10 of 11
Add the "Windy City" to your tri calendar with this long-running event that starts in the water of Monroe Harbor and ends with participants running through beautiful downtown Chicago.