The Las Conchas Fire was a wildfire in New Mexico, USA, in 2011. The fire started in Santa Fe National Forest and burned more than 150,000 acres, threatening Los Alamos National Laboratory and the town of Los Alamos. After five days of burning, it became the largest wildfire in New Mexico state history at the time, though it was surpassed the following year by the Whitewater-Baldy Complex Fire.