20-Week Delaware Marathon Training Plan

The 2027 Delaware Marathon is scheduled for April 18, 2027, so the 20-week window opens around November 29, 2026. Treat that as the outside edge of the window, then line week one up with the plan's normal weekly rhythm.

Use the longer window to make the early build calmer, not to add five months of hard training. The plan should begin close to your current load, hold most running easy, and delay the biggest race-specific work until the middle of the cycle. The course does not change the opening load you can handle, so choose from your current mileage and recent longest run before adding race-specific terrain.

Build general durability first. Add the race's hills, flat sustained running, downhill exposure, heat, or humidity in layers after the weekly rhythm is stable, then make the final long runs the most course-specific. Train for the Delaware Marathon by front-loading hills into your long runs and then holding goal pace on flat ground when your legs are already tired. The course hands you its climb between miles 6 and 7, about 180 feet, and then gives you thirteen flat trail miles in which every second you overspent early comes back out of your account.

Do not double weeks or cram missed mileage into the remaining calendar. Use your current mileage, recent longest run, experience, goal, and available days to choose a plan that can enter at an appropriate point while preserving the taper.

Only in the first half. The city loop through Wilmington carries the day's real climb, about 180 feet between miles 6 and 7, plus smaller rises through Brandywine Park and the parkways. From roughly halfway the Jack Markell Trail toward New Castle is flat, with only short bridges and overpasses to break it up.

Seven hours from the 7 a.m. start, which works out to a 16 minute per mile pace. Water stations sit roughly every mile and a half along the route. Dogs are not allowed on the course, and headphones are permitted although the organizer discourages them for safety reasons.