Flamstead is a village and civil parish in north-west Hertfordshire, England, close to the junction of the A5 and the M1 motorway at junction 9. The name is thought by some historians to be a corruption of the original Verulamstead. Flamstead stands on a ridge above the River Ver, which runs on its north side; to the south the village extends downhill to the adjoining hamlet of Trowley Bottom.