View some of the best Half Marathon races in Round Rock, Texas! RaceMob's race calendar allows you to find races that suits your needs. Use our advanced filters below or calendar on the right, and discover new races. We try to maintain up to date information, and rely heavily on our community of volunteers. If you find a race that we're missing, use the "Suggest Race" button on the right. Find RaceMob discounts that others have added or add deals that you've discovered.