The blaze began at the edge of Harris County near Plum Grove and burned into Montgomery County.
It had spread to between 80 and 100 acres by Sunday evening, officials said.
Seventeen fire departments responded, using tractors and a helicopter to control the flames and keep them from advancing past the San Jacinto River and threatening homes on the other side.
A few homes and pipeline were in the path of the fire, but no major damage or injuries have been reported.
Officials said the cause of the fire is unknown.
Please stay with Eyewitness News and abc13.com as this story continues to develop.
