Firefighters were on scene of a rapidly spreading grass fire near the 401 overpass on Highbury Avenue South.
The London Fire Department says it received numerous calls about a fire that broke out in a field next to the westbound 401 on-ramp around 5:30 p.m. Thursday.
Multiple fire units were on scene dousing hot spots to keep flames away from the Buchanan electrical substation and Peterbilt facility.
Windy conditions made extinguishing the fire difficult, though crews reported most of the fire was out around 6:30 p.m.
Ontario Provincial Police temporarily restricted access to the 401 near Highbury while crews worked on the blaze.
Fire officials say approximately five acres of land was burned.
The fire department has not confirmed the cause of the fire, but asked people to refrain from throwing lit cigarettes out of car windows, especially during dry conditions.