Fire crews first responded to the fire at about 2 p.m. and worked through Monday night to contain it. The fire was located near mile marker 22 on U.S. Highway 64.
"They pretty much have it contained," said Pat Willetto, lead dispatcher for the Bureau of Indian Affairs Division of Forestry and Wildland Fire Management, on Tuesday afternoon.
About 16 crew members from the bureau contained Monday's fire, after several other departments from San Juan County initially responded.
Though the fire threatened several structures, none were damaged. No injuries were reported.
The cause of the fire is not yet known, though the bureau suspects it may have started as a controlled burn.
The Navajo Nation Forestry Department is investigating it and several other fires in the same area.
Several other fires occurred in the same area over the past week, a handful of them burning between 70 and 80 acres each.
All of them have been near the San Juan River, where the soil is softer, making it difficult for fire department vehicles to navigate. Native grasses and salt cedar were the main fuels for the fires.
It is not known if the fires were connected.
The fires may have started as controlled burns, according to Alex Becenti, forest manager for the Navajo Nation Forestry Department. Local farmers are now burning off their land before planting season, he said.
"Be cautious while you're out there. Check the conditions, and notify the local law enforcement if need be," Becenti said.
Because of the state's ongoing drought, this year's fire season is expected to equal last year's, which saw many large brush fires and wildfires.
"This year's looking about the same, maybe worse," Willetto said.
Jenny Kane can be contacted at email@example.com; 505-564-4636. Follow her on Twitter @Jenny_Kane.