Shortly after 5pm on Wednesday multiple fire engines responded to an area near the Jackson County Fairgrounds to reports of a grassfire.
Smoke could be seen from the amphitheater at the Expo.
The fire is believed to have been started by fireworks.
Witness Jaris Johnson of Medford said his friend started the fire when he lit a Piccolo Pete, a type of firework, and threw it up in the air. Johnson said the firework landed in dry grass and quickly spread to nearby trees.
Johnson also said he and his friends tried to put out the fire using buckets of water, but it quickly spread.
When NBC 5 left the scene, fire crews appeared to have the blaze under control.