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

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