Trehko tracks 15 endurance events in Delaware, including 15 Running events. Whether you're searching for your first 5K, a Boston qualifier marathon, a local triathlon, or a trail ultra, Delaware has a race for every athlete. Use Trehko to compare registration fees and deadlines side by side, save your target races, and get automated reminders before registration opens or closes. All races listed below link directly to their official registration pages.