Hertfordshire Half Marathon & 10k November 2026

Join us for the Hertfordshire Half Marathon & 10K on Sunday 1st November 2026

The Hertfordshire Half Marathon & 10K 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.

Book your spot now at our Early Bird Prices!

Race Distances & Start Times

09:00 am - Half Marathon start

Elevation: 218m, Road (undulating)

Distances: 21.1m

Cut-off: 3 Hours (12:00)

09: 30 am - 10k start

Elevation: 92m, Road (undulating)

Cut-off: 1.5 Hours (11:00)

Included in the entry

Unique Themed Medal 

Chip Timed Results

Post-race goodies

Free Race Photos

Come and experience an exhilarating day of running in the scenic surroundings of Knebworth. We can't wait to welcome you to the start line!

With RunThrough you can expect a friendly team of marshals to help guide you round the course and cheer you on to the finish, a lively and well-serviced event village with plenty of food and drink options, and free goodies from our partners at the finish line after your hard effort.

We have been extensively researching what runners consider important, and sustainability is fast becoming the top issue. Click here to see what RunThrough is doing for sustainability.

T-Shirts at events have become a hot topic with concerns around the quality not being high enough to wear on a regular basis. We have decided to tackle this by offering a RunThrough Kit Technical T-Shirt with a retail value of £22 for £12 with the addition of the Hertfordshire logo printed on the chest.

We can do this with our partner RT Kit as part of a strategic decision to raise awareness about the quality of the product whilst reducing the overall cost of events for those who would prefer not to have a t-shirt included.