May 18, 2019

Murrell Park, Flower Mound, Texas
Race Start: 8:00 a.m.

This is an off-road triathlon and includes a 1200-meter swim, a 13.4 mile mountain bike and a 5.6 mile run. The race will take place on the most popular trail in the DFW Metroplex, Northshore trail on Lake Grapevine. The start will take place at Murrell Park (about midway on the one-way looped course). The swim will be in a cove at an out of service boat ramp. The mountain bikers will enter the course and travel in a counter clockwise direction, heading east first to do Loops 2, 3 & 4, and then to west on loops 1 and 5. This loop is fast, with a few technical sections to challenge you. The runners will head east on a counter clockwise loop of flowy single track.

Register for the Rock Dallas Triathlon


Recognition of Your Awesomeness

Podium Categories

Male & Female – 3 deep
Physically Challenged
Male & Female – 3 Deep

Age Groups: – 3 Deep
Males: 15-19, 20-24, 25-29, 30-34, 35-39, 40-44, 45-49, 50-54, 55-59, 60-64, 65-69, 70-74, 75+
Females: 15-19, 20-24, 25-29, 30-34, 35-39, 40-44, 45-49, 50-54, 55-59, 60-64, 65-69, 70-74, 75+


Murrell Park, Flower Mound, Texas

Murrell Park is located on the north side of Lake Grapevine and is operated by the Army Corps of Engineers. This park sits on the bluffs of the north shore overlooking the main lake.

Day use is Free at Murrell Park. White Chalk Rd area start/finish/transition only open on race day.

Camping is available for $10/night. However, reservations are required. Reserve early at Reserve America

Extra Bits


*Right to Cancel or Reschedule – Terra Firma Racing LLC reserves the right in the event of inclement weather, emergency, or natural disaster to cancel the race or move to a later time that day or alternate date within the year (if available). In the event of a CANCELLATION with no ability to reschedule, there will be NO REFUND OF ENTRY FEES.  Each athlete must accept any such risk for their entry paid. That said, we have never had to cancel the DIRTY DOZEN MOUNTAIN BIKE RACE yet. We even had snow one year. We did have to shorten the course to 8 hours instead of 12 though.