A driver caught footage on his dash cam of a grass fire near the Stoke Hammond bypass on Monday evening.
Buckinghamshire Fire and Rescue Service were at the scene at 5.55pm.
An area of grass verge measuring about 60m x 10m was alight near the A4146 northbound.
The service sent one appliance and crew from Bletchley and one from Leighton Buzzard attended.
Firefighters used one hose reel.