The Hertfordshire Half Marathon & 10K in support of Garden House Hospice returns for 2026, and registration is now OPEN! Taking place on Sunday 1st November, this exciting event is set in beautiful Old Knebworth, offering runners of all abilities a memorable race experience.Both races feature undulating, scenic road routes through the picturesque Hertfordshire countryside. Whether you're tackling the Half Marathon or the 10K, you'll enjoy a welcoming race-day atmosphere, excellent support from marshals, and clear route markings. It's the perfect autumn challenge for seasoned runners aiming for a new PB or first-timers stepping up their distance.
Download Dangelo, pick RunThrough Hertfordshire Half Marathon & 10k from the race list, and get a structured plan built around race day, with pace targets from your own running and workouts synced to Garmin & Coros.
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5 weeks
Start now: about 5 weeks left (shortened plan).
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Start this plan in the app →Dangelo shortens the build to fit the time you have left, and you'll still get a structured, achievable plan for RunThrough Hertfordshire Half Marathon & 10k.
Every week counts back from 1 November, so base, build, peak and taper land exactly where they should.
Dangelo reads your recent training from Garmin and Coros and sets workout paces you can actually hold, then adapts them as you get fitter.
Racing more than once? Add every event and the Race Calendar builds one connected plan that bridges the gaps between them.