The fire has burned less than an acre in the northwest corner of the park by Bighorn Pass Trailhead.
The fire was caused by lightning and detected by hikers in the area. In a news release from Yellowstone National Park, officials say firefighters are suppressing the ground fire and it is considered under control.
Despite the ignition, fire danger remains low in the park.
Last year Yellowstone saw 9 fires, all burning under 5 acres between June and September.