Nearly 600 homes in Jefferson County were evacuated overnight Wednesday after a wildfire broke out near Deer Creek Canyon, sheriff’s officials said.

As of 1 a.m. Wednesday, the Quarry fire was burning on 100 acres of Jefferson County land just west of Grizzly Drive and still growing, according to the sheriff’s office. The cause of the fire remains unknown.

Evacuations started just before midnight Tuesday when sheriff’s officials announced mandatory evacuations for the Deer Creek Mesa, Sampson and Maxwell subdivisions southwest of Ken Caryl.

County officials said the fire was discovered by a sheriff’s deputy around 9 p.m. and was moving southeast.

By 1 a.m. Wednesday, 300 homes in the three subdivisions were being evacuated as deputies and firefighters knocked on doors and sent out emergency alerts, sheriff’s officials said.

As the fire continued to grow overnight, sheriff’s officials announced mandatory evacuations for another 275 homes in the McKinney and Murphy subdivisions.

Multiple agencies responded to the late-night blaze, including crews from West Metro Fire Rescue, South Metro Fire Rescue, Inter-Canyon Fire, the North Folk Fire Department and Jefferson County Open Space.

This is a developing story and will be updated.