Update 7:45 p.m.:
The scene is clear and all lanes are reopened on the highway.
Original story 6:20 p.m.:
Bradford West Gwillimbury Fire and Emergency Services responded to a report of a grass fire on Highway 400 at 10th Line in Bradford today.
The call came in at approximately ten after four this afternoon.
Crews found about 300 metres of brush and grass burning along the side of the highway.
OPP and road crews closed the right two lanes to make room for fire crews to work safely.
As of 5:15 p.m., firefighters are still working to quench the hot spots and the highway is still down to one lane.
If you are heading north, please find an alternate route as the 400 is backed up beyond Highway 88.